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Welsbach & General Gas Mantle EPA Superfund Record of Decision

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General Gas Mantle Company (GGM), was located in Camden, New Jersey. GGM operated from 1915 to approximately 1940. Thorium, Uranium, Radon, Thoron, Gamma Radiation
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EPA/ROD/R02-99/028 1999

EPA Superfund Record of Decision:

WELSBACH & GENERAL GAS MANTLE (CAMDEN RADIATION) EPA ID: NJD986620995 OU 01 CAMDEN AND GLOUCESTER CIT, NJ 07/23/1999

RECORD OF DECISION DECISION SUMMARY Welsbach/General Gas Mantle Contamination Site Glouster City & Camden, Camden County, New Jersey

United States Environmental Protection Agency Region 2 New York, New York July 1999

DECLARATION FOR THE RECORD OF DECISION

SITE NAME AND LOCATION Welsbach/General Gas Mantle Contamination Superfund Site Gloucester City & Camden, Camden County, New Jersey

STATEMENT OF BASIS AND PURPOSE This Record of Decision (ROD) documents the U.S. Environmental Protection Agency's selection of a remedial action to address soil and building material contamination at the Welsbach/General Gas Mantle Contamination Site (the Site), in accordance with the requirements of the Comprehensive Environmental Response, Compensation and Liability Act of 1980, as amended (CERCLA), 42 U.S.C. 9601-9675, and to the extent practicable, the National Oil and Hazardous Substances Pollution Contingency Plan (NCP), as amended, 40 CFR Part 300. This decision document explains the factual and legal basis for selecting the remedy for the first operable unit of this Site. The New Jersey Department of Environmental Protection (NJDEP) has been consulted on the planned remedial action in accordance with Section 121 of CERCLA. The NJDEP concurs with the selected remedy (see Appendix IV). The information supporting this remedial action is contained in the Administrative Record for the Site, the index of which can be found in Appendix III of this document.

ASSESSMENT OF THE SITE Actual or threatened releases of hazardous substances from the Welsbach/General Gas Mantle Contamination Site, if not addressed by implementing the response action selected in this ROD, may present an imminent and substantial endangerment to public health, welfare, or the environment. DESCRIPTION OF THE SELECTED REMEDY The remedy described in this document represents the first of three planned remedial actions or operable units for the Welsbach/General Gas Mantle Contamination Site. It will address radiologically-contaminated soil and building materials at the former Welsbach and General Gas Mantle facilities and properties in the vicinity of these facilities. For the second operable unit at the site, the current owner of the former Welsbach facility is performing a remedial investigation and feasibility study on the last remaining Welsbach era building. A third operable unit is planned to investigate potential site impacts to groundwater, surface water, sediments, and wetlands. The major components of the selected remedy include:

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Excavation/removal of soil and waste materials with radiological contamination above remedial action objectives from the former Welsbach and General Gas Mantle Facilities: Excavation/removal of soil and waste materials with radiological contamination above remedial action objectives from the residential and commercial properties in the vicinity of two former gas mantle facilities; Off-site disposal of the radiologically-contaminated soil and waste materials; Decontamination and demolition of the General Gas Mantle Building; and Appropriate environmental monitoring to ensure the effectiveness of the remedy.

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DECLARATION OF STATUTORY DETERMINATIONS The selected remedy meets the requirements for remedial actions set forth in Section 121 of CERCLA, in that it: (1) is protective of human health and the environment; (2) complies with Federal and State requirements that are legally applicable or relevant and appropriate to the extent practicable; (3) is cost-effective, and (4) utilizes permanent solutions and alternative treatment (or resource recovery) technologies to the maximum extent practicable. However, because treatment of the principal threats of the Site was not found to be practicable, this remedy does not satisfy the statutory preference for treatment as a principal element. Because this remedy will not result in hazardous substances remaining on the remediated properties above levels that allow for unlimited use and unrestricted exposure, a five-year review of this action will not be required. I certify that the remedy selected for this Site is protective of human health and the environment.

TABLE OF CONTENTS page SITE NAME, LOCATION AND DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 SITE HISTORY AND ENFORCEMENT ACTIVITIES . . . . . . . . . . . . . . . . . . . . . . . 2 HIGHLIGHTS OF COMMUNITY PARTICIPATION . . . . . . . . . . . . . . . . . . . . . . . . . 4 SCOPE AND ROLE OF RESPONSE ACTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 THE NATURE OF RADIONUCLIDES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 SUMMARY OF SITE CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 SUMMARY OF SITE RISKS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 REMEDIAL ACTION OBJECTIVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 DESCRIPTION OF REMEDIAL ALTERNATIVES . . . . . . . . . . . . . . . . . . . . . . . . . 16 SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES . . . . . . . . . . . 21 SELECTED REMEDY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 STATUTORY DETERMINATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 DOCUMENTATION OF SIGNIFICANT CHANGES . . . . . . . . . . . . . . . . . . . . . . . . 29

APPENDICES APPENDIX I APPENDIX II APPENDIX III APPENDIX IV APPENDIX V FIGURES TABLES ADMINISTRATIVE RECORD INDEX STATE LETTER RESPONSIVENESS SUMMARY

SITE NAME, LOCATION AND DESCRIPTIONSite Background The Welsbach/General Gas Mantle Contamination site (Welsbach/GGM or Site) is a multiproperty site located in Gloucester City and Camden, Camden County, New Jersey. EPA initially identified the Site in 1980 during an archive search conducted as part of the investigation of the U.S. Radium Corporation Superfund site located in Orange, New Jersey. Historical U.S. Radium Corporation files indicated that radiological materials were purchased by U.S. Radium from the Welsbach Corporation during the 1920s. Between the 1890s and 1940s, the Welsbach Company (Welsbach) manufactured gas mantles at its facility in Gloucester City, New Jersey. Welsbach was a major manufacturer and distributer of gas mantles until gas lighting was replaced by the electric light. Welsbach extracted the radioactive element thorium from monazite ore and used it in the gas mantle manufacturing process. Thorium causes the mantles to glow more brightly when heated. A second gas mantle manufacturing facility, known as the General Gas Mantle Company (GGM), was located in Camden, New Jersey. GGM operated from 1915 to approximately 1940. In May 1981, EPA conducted an aerial radiological survey of the Camden and Gloucester City area to investigate for radioactive contaminants. The survey encompassed a 20 square kilometer area surrounding the former locations of the Welsbach and GGM facilities. Five areas with elevated gamma radiation were identified from the aerial survey; they included the locations of the two former gas mantle manufacturing facilities and three mainly residential areas in both Camden and Gloucester City. In 1993, EPA reanalyzed the data from the aerial survey. Based on this revised information, EPA identified a sixth potential radiologically-contaminated area which includes two vacant lots in Gloucester City. In the early 1990s, NJDEP conducted detailed radiological investigations at more than 1,000 properties located throughout the original five study areas. Radiological contamination was identified at the two former gas mantle facilities and at approximately 100 properties located near the two facilities. In 1996, the Welsbach/GGM site was placed on National Priorities List (NPL) because of the presence of radioactive contaminants. EPA divided the Welsbach/GGM site into six study areas in Camden and Gloucester City, New Jersey (Figure 1). A brief description of each study area and its current land use is presented below: Study Area One: includes the former GGM Facility and residential and commercial properties which surround the facility (Figure 2.) The former GGM Facility is located in a mixed industrial, commercial, and residential zoned section of Camden.

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Study Area Two: includes the location of the former Welsbach Facility and nearby residential/commercial properties. The former Welsbach Company is situated in industrial zoned section of Gloucester City with residential properties to the immediate east (Figure 3.) Study Area Three: includes residential and recreational properties in Gloucester City, including the Gloucester City Swim Club and the Johnson Boulevard Land Preserve. Study Area Four: includes residential properties in the Fairview section of Camden. Study Area Five: includes residential properties, vacant land properties, and two municipal parks near Temple Avenue and the South Branch of Newton Creek in Gloucester City. Study Area Six: includes two vacant lots in a residential zoned area of Gloucester City.

SITE HISTORY AND ENFORCEMENT ACTIVITIES The Welsbach and the GGM Facilities have complex histories of changes in name, ownership, and operation. Specific details are discussed in the paragraphs below. The United Gas Improvement Company, which formed Welsbach, purchased the patent rights to manufacture thorium-containing gas mantles in the 1880s from Dr. Carl Auer von Welsbach. The process for manufacturing the Welsbach gas mantle used a highly purified solution of 99 percent thorium nitrate and 1 percent cerium nitrate as a "lighting fluid" in distilled water. A fabric sock was then dipped into the thorium solution to create the gas mantle. Thorium caused the gas mantle, when lit, to give off a very bright white light. The commercial source of thorium and cerium is a mineral known as monazite sand. Monazite sand contains approximately 5-6 percent thorium oxide and 20-30 percent cerium oxide. Thorium was typically extracted from the monazite ore by heating the ore in a sulfuric acid solution. The thorium and other rare earth elements would go into solution, while the radium-228 remained in the tailings of insoluble sulfates. Around 1915, Welsbach started using and selling the radium-228 for use in luminescent paint. For a number of years, Welsbach was the largest manufacturer of gas mantles in the world, making up to 250,000 mantles per day at its peak. Welsbach also made gas room heaters, gas storage water heaters, gas and electrical fixtures, electrical refrigerators, plumbing supplies and lacquers. Manufacturing operations at the Welsbach facility began as early as 1882 and lasted until the 1940s. The facility property covered an area of about 21 acres, and consisted of about 20 buildings.

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In 1942, the U.S. Government acquired the Welsbach Facility and sold it to the Randall Corporation in 1948. Randall leased the property to the Radio Corporation of America. Victor Division. A series of intervening owners followed. In May,1976, the property was purchased by Holt Hauling and Warehousing, Inc. (Holt), the current owner of the property. Holt operates a cargo and overseas shipping business. None of the owners of the property after Welsbach dealt with radioactive materials. Only one Welsbach era-building, the Armstrong Building, is still present on the property. There is no information available on when the other Welsbach-era buildings were demolished. The remedy for the Armstrong Building is not part of this decision. The former gas mantle manufacturing facility in Camden was owned and operated by the GGM Company from 1912 to 1941. There is little information available regarding activities at GGM, other than it used and resold radium and thorium. Between 1941 and 1978, there was a total of seven different private owners of the property. Based on current information, none of these operations involved radioactive materials. In January 1978, the southern portion of the property was purchased by the Dynamic Blending Company. In October 1988, the northern portion of the property was purchased by Ste-Lar Textiles. In 1992, NJDEP removed radiologically-contaminated fabrics, relocated Ste-Lar, and sealed up the GGM building on the northern property to restrict access. During the years that Welsbach and GGM operated, ore tailings were used for fill at properties in the vicinity of the facilities. It is also reported that building debris from the former Welsbach Facility may have been disposed of as fill in the area. In addition, workers from the former Welsbach and GGM Facilities may have brought contamination home with them. These properties associated with radiological waste from the Welsbach and GGM Facilities are collectively termed Vicinity Properties. In 1991, NJDEP initiated a radiological investigation at more than 1,000 properties located throughout Study Areas 1 through 5. At properties where NJDEP determined that exposure levels were unacceptable (or posed an immediate health risk), it performed interim remedial measures. These measures included the installation of radon/thoron ventilation systems and placement of concrete or lead sheeting to shield gamma radiation. In addition, NJDEP restricted access to outdoor areas which exceeded its action levels. In 1998, EPA identified a 100 square foot area in a Gloucester City Park, located in Study Area 5, that had elevated levels of gamma radiation at the surface. In December 1998, EPA performed a removal action to reduce exposure to these elevated levels. EPA excavated the top three feet of radiologically-contaminated soil, disposed of this soil off-site at a permitted facility, and replaced the waste material with clean fill.

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Both the Welsbach Company and the GGM Company went out of business in the early 1940s, and EPA has been unable to identify any successor companies. In September 1997. EPA entered into an Administrative Order on Consent (AOC) with Holt, the current owner of the former Welsbach Facility. Under the terms of the AOC, Holt agreed to perform a Remedial Investigation and Feasibility Study (RI/FS) on the Armstrong Building. Holt has also submitted information to support its position that it is not liable for response costs at the former Welsbach facility. EPA is currently evaluating this information.

HIGHLIGHTS OF COMMUNITY PARTICIPATIONThe RI/FS report, the Proposed Plan and supporting documentation were made available to the public in the administrative record file at the Superfund Document Center at EPA Region II, 290 Broadway, 18th Floor, New York, New York 10007 and at the following repositories: City of Camden Main Library, 418 Federal Street, Camden, New Jersey 08103; the Hynes Center, 1855 South 4th Street, Camden, New Jersey 80104; and the Gloucester City Public Library, Monmouth and Hudson Streets, Gloucester City, New Jersey 08030. Notices of availability for the documents in the administrative record were published in the Philadelphia Inquirer on February 1, 1999, the Courier-Post on February 2, 1999, and the Gloucester City News on February 4, 1999. The public comment period which related to these documents was held from February 1, 1999 to March 3, 1999. EPA conducted public meetings in both Gloucester City and Camden to inform local officials and interested citizens about the Superfund process, to review proposed remedial activities at the Site and receive comments on the Proposed Plan, and to respond to questions from area residents and other interested parties. Meetings were held on February 23, 1999, at the Pine Grove Fire Station #2 in Gloucester City, and on February 24, 1999, at the Camden County Municipal Utilities Authorities Auditorium in Camden. Responses to the comments received at the public meeting are included in the Responsiveness Summary (see Appendix V). The City of Gloucester City submitted a resolution supporting the proposed remedy. No other written comments were received during the public comment period. This Record of Decision (ROD) document presents the selected remedial action for the Welsbach/GGM site, chosen in accordance with the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA), as amended by the Superfund Amendments and Reauthorization Act, and, to the extent practicable, the National Oil and Hazardous Substances Pollution Contingency Plan (NCP). The selection of the remedy for this site is based on the administrative record.

SCOPE AND ROLE OF RESPONSE ACTIONThis action is the first operable unit or phase taken to address the radiological contamination at the Site. This action will address the radiologically-contaminated soil and building materials at the Vicinity Properties and the former Welsbach and GGM Facilities. For the second operable

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unit at the site, Holt is performing an RI/FS for the Armstrong Building. A remedy for this second operable unit will be selected in a future ROD. A third operable unit is planned to investigate potential site impacts to groundwater, surface water, sediments, and wetlands.

THE NATURE OF RADIONUCLIDESA radionuclide is an element that spontaneously changes or decays into another element through natural processes. Radionuclides are present in trace amounts in all rocks and soils, and consist primarily of elements of the uranium-238 and thorium-232 decay series. There are approximately 1,700 different unstable atomic species or radionuclides. These include both naturally occurring and man-made radionuclides. The radionuclides of concern in the wastes which originated at the former Welsbach and GGM Facilities are members of the uranium and thoriurn decay series. There are 14 unique radionuclides in the uranium decay series and 11 unique radionuclides in the thoriurn decay series which precede the formation of stable lead (Pb-206 or Pb-208). Alpha, beta, and gamma radiation are emitted from the various members of the two decay series. The primary nuclides of concern are Thorium-232,-Radium-226, and radon gas (Radon-222 and Radon-220.) Each radionuclide has its own unique characteristic fingerprint, consisting of three parameters: ! ! The radioactive half-life describes the amount of time in which half of any given number of atoms of a radionuclide will decay. The mode of decay refers to the type(s) of particles or electromagnetic rays emitted from the radionuclide as it decays. These types include alpha and beta particles, and gamma rays. The amount of energy carried away from the atom by the particles or rays is radionuclide specific. It is the transfer of this energy to living tissue which may cause biological effects.

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When radionuclides decay, they emit energy in the form of radiation. The decaying radionuclide is often called the parent, and the radionuclide produced is called the decay product. A quantity of radioactive material is measured by its rate of decay, expressed by the unit Curie (Ci), which is equal to 2.22 x 1012 (2.22 trillion) disintegrating atoms per minute. A more convenient unit for expressing environmental radioactivity is the picoCurie (pCi), which is equal to 1 x 10-12 (one trillionth) Ci. Table 1 summarizes the common units of measure for radionuclides that are discussed below. Radium-226 is a naturally occurring, radioactive, metallic element formed from the decay of uranium. In its decay, Radium-226 forms Radon-222 or radon gas. Radon gas is colorless, odorless, radioactive and inert; therefore, it can move easily through soil to the ground surface or 5

into houses, Within a matter of days, the radon gas itself decays into a series of radioactive decay products. While radon gas in the outdoor air dissipates quickly, the concentration of radon decay products in the indoor air can build up over time. Exposure to the energy released by these various decaying atoms can result in adverse health effects. For radon decay products, a special unit called Working Level (WL) has been developed. Working Level is defined as any combination of short-lived radon decay products in 1 liter of air that will result in the ultimate emission of 1.3 x 105 Mega-electron Volts of potential alpha energy. This value is approximately equal to the alpha energy released from the decay of progeny in equilibrium with 100 pCi of Radon-222. Thorium-232 is also a naturally occurring radionuclide and is the initial radionuclide of the thorium decay series. Its decay products include Radium-228 and Radon-220. Radon-220 is also known as thoron. Thoron and its decay products have extremely short half-lives that usually prevent them from concentrating to any appreciable extent in indoor air. However, if a significant source of thoron exists within, beneath, or adjacent to a structure (such as the thorium and Radium-228 found in Welsbach/GGM site wastes), thoron decay products can reach concentrations which create health risks.

SUMMARY OF SITE CHARACTERISTICSIn September 1997, EPA started an RI to characterize the nature and extent of contamination at the Welsbach Facility, GGM Facility, and 20 of the radiologically-contaminated properties identified by NJDEP in the vicinity of Welsbach and GGM. The work was conducted by Malcolm Pirnie, Inc., under contract to EPA. In order to develop a cleanup strategy for the Site, the RI field investigations were divided into three property categories, as follows: ! ! ! Former Welsbach Company Facility; Former General Gas Mantle Company Facility; Vicinity Properties

Property Investigations EPA conducted both chemical and radiological characterizations of the former Welsbach and GGM Facilities to define the went of contamination. EPA also performed a radiological investigation on 20 of the potentially contaminated Vicinity Properties identified by NJDEP. Only 20 Vicinity Properties were investigated during the RI so that EPA could confirm the NJDEP data and expedite the development of cleanup alternatives. Based on evaluation of the NJDEP data, EPA segregated the properties investigated by NJDEP into the following three categories. Table 2 summarizes the results of the property classification. 1) Properties where there is no evidence of contamination related to the Welsbach/GGM site. These are properties which have surface exposure rates less than 13 R/h, radon progeny

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measurements less than 0.02 WL, and radon gas levels less than 4.0 pCi/l. The exposure rate represents the upper level of the range of natural background. 2) Suspect Properties - are properties for which either elevated levels (i.e., above background) of radioactivity were detected by NJDEP or properties situated adjacent to known contaminated properties; and 3) Contaminated Properties - are properties with levels of radioactivity which potentially warrant remedial action (i.e. properties with either exposure rates greater than 30 R/h., radon progeny greater than 0.02 WL, radon gas levels greater than 4.0 pCi/l, or thorium or radium concentration in the soil greater than 5 pCi/g.) EPA will investigate the remaining Contaminated Properties which were not studied in the RI and the Suspect Properties during the remedial design phase of this cleanup. EPA estimates that it will study about 600 properties during the design phase to determine exactly which properties require cleanup. This additional work may include sampling for chemical analysis, where deemed appropriate when considering past ownership and historic information. Table 3 summarizes the volume of contaminated soil and debris at the Contaminated Properties. Field activities conducted as part of the RI included the following: ! ! ! ! ! ! ! ! Radon measurements Radon decay product Working Level measurements Gamma radiation surface and one-meter height exposure rate surveys Surface and subsurface soil sampling Downhole gamma radiation logging Total surface beta surveys and removable surface alpha and beta sampling Structural materials sampling for radionuclides (in some buildings) Chemical sampling for metals, volatile organic compounds, and semi-volatile organic compounds at the two former gas mantle facilities

The results of the RI can be summarized as follows. Former Welsbach Facility Investigation Most of the radiological contamination is located in the area of what is believed to be the location of a former Welsbach building that was demolished in the 1970s. This area is currently used for storage. However, there are smaller areas of contamination scattered throughout the property. The soil in these areas is contaminated with elevated concentrations of the thoriurn and uranium decay series radionuclides. These radionuclides are principal threat wastes. Subsurface contamination on the Welsbach facility averages about 11 feet in depth. An estimated 27,200 cubic yards of soil/buried debris have thoriurn and/or radium concentrations exceeding 5 pCi/g. Radium and thorium, concentrations in soil ranged from background (about 1 pCi/g for each) to as high as 455 pCi/g and 1,190 pCi/g, respectively. Surface gamma exposure

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rates associated with the contaminated soils ranged from background (less than 10 micro Roentgen per hour [/R/h]) to 780 R/h. The highest readings were associated with a large fill area identified in the middle of the storage area. Low levels of chemical contaminants were also identified at the former Welsbach Facility. Contaminants of potential concern include semi-volatile organic compounds and arsenic. These contaminants may be indicative of Historic Fill. If this is confirmed during the remedial design and these contaminants are not comingled with the radiological contaminants of concern, then there may be a need to remediate such historic contaminants. Former General Gas Mantle Facility Investigation Elevated concentrations of thorium and uranium decay series radionuclides were identified in soils on the former GGM property. Contamination was generally limited to the top six to eight feet, although contamination in some areas of South Fourth Street and the GGM Courtyard ranged from 12 to 16 feet in depth. An estimated 900 cubic yards of soil have thorium and/or radium concentrations which exceeded 5 pCi/g. Radium and thorium concentrations in soil ranged from background to as high as 172 pCi/g and 149 pCi/g, respectively. Surface gamma exposure rates associated with the contaminated soils ranged from background (less than 10 R/h) to 380 R/h. Only localized areas of surface contamination were identified outdoors. Most of the outdoor contamination is located in the area of South Fourth Street. However, EPA identified some smaller areas of contamination in the alleyway behind the property. The contamination also extended onto some backyards of neighboring residential properties. Elevated levels of surface contamination were observed in many areas inside the former GGM building. Levels as high as 2.33 microCi per square meter(Ci/m2 ) were observed. Indoor gamma exposure rates ranged from background to 900 R/h. An estimated 1,460 cubic yards of contaminated structural materials in the building itself were identified, with thorium concentrations as high as 750 pCi/g. In the basement of the former GGM building, radon decay product concentrations measured 1.7 WL, compared to an average background level of 0.005 WL. Certain semi-volatile organic compounds and metals were identified in the outdoor portions of the former GGM Facility. These were, however, at such low levels that they are not of concern. These contaminants may be indicative of Historic Fill. If this is confirmed during the remedial design and these contaminants are not comingled with the radiological contaminants of concern, then there may be a need to remediate such historic contaminants.

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Vicinity Property Investigation EPA investigated 20 properties in Camden and Gloucester City for radiological contamination as part of the RI. EPA compared the data from these properties to information collected from earlier NJDEP investigations on over 1000 properties and determined that the data were comparable. Contaminated soil averaged about two to three feet in depth on most residential properties. On a few properties, contamination extended to 10 feet in depth. Some site properties have indoor radon gas concentrations or soil radionuclide concentrations which pose a long-term risk to human health. Based on the comparison of EPA and NJDEP data, EPA identified a total of 54 properties as having contamination above the cleanup levels. During the remedial design phase, EPA will delineate the extent of contamination on each of these properties in order to design a cleanup plan for each property. During the remedial design, EPA will also investigate approximately 600 additional properties that are either adjacent to the known contaminated properties or have gamma exposure rates slightly above background levels. If contamination above the cleanup objectives is found on any of these Suspect Properties, EPA will delineate the extent of this contamination and design a cleanup plan for those properties. Based on its review of the NJDEP data, EPA determined that 449 out of the approximately 1,000 properties NJDEP investigated showed no evidence of contamination. These properties had surface gamma exposure rates less than the upper range of natural background, radon progeny less than 0.02 WL, and radon gas levels below 4.0 pCi/l. Current and Future Land Use The site properties and the surrounding areas consist of industrial, commercial, and residential zoning districts. Study Area 1 is located in an industrial-zoned section of Camden with residential properties east of the former GGM Facility. In Study Area 2, the former Welsbach Facility is situated in an industrial-zoned section of Gloucester City with residential properties to the immediate east. Study Area 3 consists of residential properties, a private swim club, and a land preserve. Study Area 4 consists entirely of residential properties. Residential properties and two municipal parks comprise Study Area 5. Study Area 6 consists of vacant land in a residential area. No significant changes in land use are anticipated, except in the area of GGM where there is a possibility that some residential areas may be rezoned for commercial uses. The former GGM facility is bordered by residential homes located on Arlington Street in Camden. Most of the homes on Arlington Street are abandoned and there is debate within the community, given the industrial nature of the area, whether to rezone this area to allow for commercial development or leave it residential. Whether zoning changes will actually be made is uncertain at this time.

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SUMMARY OF SITE RISKSA baseline risk assessment was conducted for the former Welsbach Facility, the former GGM Facility, and the Vicinity Properties using analytical data obtained during the RI. The baseline risk assessment estimates the human health risk which could result from the contamination at a site if no remedial action were taken. Ecological risks, that is, the risks to aquatic and terrestrial wildlife, were not evaluated for this operable unit. However, EPA compared the levels of radioactive exposure to various species with the cleanup criteria. Based on this comparison, EPA determined that the cleanup criteria will be protective of ecological receptors for this operable unit. An Ecological Risk Assessment will be conducted in a future RI to evaluate the potential for adverse effects to aquatic and terrestrial wildlife in accordance with Ecological Risk Assessment Guidance for Superfund, Process for Designing and Conducting Ecological Risk Assessments (EPA 540-R-97-006). To evaluate human health risks, a four-step process was used for assessing site-related risks for a reasonable maximum exposure scenario. These steps are: Hazard Identification - identified the contaminants of concern at the site based on several factors such as toxicity, frequency of occurrence. and concentration; Exposure Assessment - estimated the magnitude of actual and/or potential human exposures, the frequency and duration of these exposures, and the pathways (e.g., ingesting contaminated soil) by which humans are potentially exposed; Toxicity Assessment - determined the types of adverse health effects associated with exposures to site contaminants, and the relationship between magnitude of exposure dose) and severity of adverse effects (response); and Risk Characterization - summarized and combined outputs of the exposure and toxicity assessments to provide a quantitative (e.g., one-in-a-million excess cancer risk) assessment of site-related risks. For risk assessment purposes, individual contaminants are typically separated into two categories of health hazard depending on whether they exhibit carcinogenic effects (causing cancer) or noncarcinogenic effects (causing health effects other than cancer.) Radionuclides from the uranium and thoriurn decay series (e.g., radium, thorium, radon, and radon decay products) are known human carcinogens. Nonradiological chemical contaminants (e.g., PAHs and arsenic) may exhibit both carcinogenic and noncarcinogenic health effects. EPA's acceptable cancer risk range is 10-4 to 10-6, which can be interpreted to mean that an individual may have a one in 10,000 to one in 1,000,000 increased chance of developing cancer because of site-related exposure to a carcinogen. EPA usually initiates remedial action at a site when the risk estimate exceeds this range. Human health risks were estimated for both radionuclides and chemicals of concern at the former Welsbach and GGM Facilities, and for radionuclides concern at the Vicinity Properties. Building materials and/or soil were the environmental media of concern. Following EPA guidance, risks were estimated based, on a reasonable maximum exposure scenario. Risks were

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estimated as a result of exposure to site-related carcinogens based on a number of assumptions that result in an overall exposure estimate that is conservative but within a realistic range of exposure. In assessing potential human health risks from exposure to the radionuclides, several scenarios were evaluated which involve exposure to external gamma radiation, ingestion of radioactive materials, and inhalation of radioactive materials. For the former Welsbach Facility, risk estimates were evaluated for current and future workers, other site workers (part-time workers), and construction workers. For the former GGM Facility, risk estimates were evaluated for current and future trespassers, and future construction workers, adult residents, child residents, and workers. At the Vicinity Properties, risk estimates were evaluated for adult and child residents of the 14 residential properties investigated, and appropriate populations at the remaining six Vicinity Properties (Jogging Track, Swim Club, Martins Lake, Public Park, Land Preserve, and the Popcorn Factory.) These risks were then compared to the risk from natural background sources of radiation. The following exposure pathways were evaluated in detail for current and future land-use conditions: ! ! ! ! ! Inhalation of radon decay products by residents, or occupants at commercial properties; Exposure to external gamma radiation emanating from thorium- and radiumcontaminated material, resulting in elevated exposures to residents/occupants; Ingestion of radionuclides in soil by residents/occupants; Ingestion of radionuclides in locally grown produce by residents; and Inhalation of radioactive particulates by residents/occupants.

The Vicinity Properties and the former Welsbach and GGM Facilities have radiogenic risk (radiation induced) cancer risk estimates, that is, the risks due solely to the presence of radioactive materials above background levels, which exceed EPAs risk range. The maximum excess lifetime radiogenic cancer risk estimates based on reasonable maximum exposures are 5.7 x 10-2 at the former Welsbach Facility (to the current and future site worker), 1.8 x 10-1 at the former GGM Facility (to a hypothetical future site worker), and 1.8 x 10-1 to a hypothetical resident of a Vicinity Property (See Tables 4 and 5.) The uranium and thorium decay series radionuclides are principal threat wastes because of these increased cancer risks. The cancer risk from chemical exposures at the former Welsbach and GGM facilities was also evaluated for the same populations as the radionuclides. Construction workers at both Welsbach and GGM would be subject to the maximum risk from the chemicals of concern (See Table 6

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and 7.) However, these cancer risks do not exceed EPAs risk range and. therefore, no additional remedial action is necessary to address chemical contaminants at these facilities. To assess the potential for cumulative noncarcinogenic effects posed by multiple contaminants. EPA has developed a hazard index (HI). The HI is derived by adding the noncancer risks for site chemicals with the same target organ or mechanism of toxicity. When the HI exceeds 1.0, there may be concern for adverse health effects due to exposure to multiple chemicals. For the Welsbach/GGM site, non-cancer health effects were evaluated only at the former Welsbach and GGM Facilities. The total HI for construction worker exposure to the chemicals of concern in soil at the former Welsbach Facility from ingestion, dermal contact, and inhalation is equal to EPAs acceptable level of 1.0 (See Table 6.) Ingestion of arsenic is the predominant contributor to the risk estimate. The total HI for construction worker exposure to the chemicals of concern in soil at the GGM Facility from ingestion, dermal contact, and inhalation is 0.03; this hazard index is below EPAs acceptable level of 1.0, indicating that adverse, noncarcinogenic health effects from such exposure are unlikely (See Table 7.) The following are the dominant radiological exposure pathway risks for the various exposure scenarios evaluated for the Welsbach/GGM site. At residential properties and the former Welsbach Facility, the majority of risk is from exposure to external gamma radiation, or direct radiation. Occupants of the former GGM Facility (current and future trespassers and future site workers) are at risk primarily from inhalation of radon decay products. Future construction worker risk is primarily due to direct radiation, although inhalation of particulates containing radioactive material also contributes a significant portion of the risk. This RI focused primarily on residential and commercial properties, and sensitive species of plants and animals are not likely to inhabit these portions of the Site. However, sensitive species may be present in Study Areas 3 and 5 around Newton Creek and associated areas of the Delaware River. An ecological risk characterization will be conducted in conjunction with the third operable unit RI to assess potential impacts to ground water, surface water, and sediment from the Site. Uncertainties The procedures and estimates used to assess risks, as in all such assessments, are subject to a wide variety of uncertainties. In general, the main sources of uncertainty include: ! ! ! ! ! environmental chemistry sampling and analysis environmental parameter measurement fate and transport modeling exposure parameter estimation toxicological data

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Uncertainty in environmental sampling arises in part from the potentially uneven distribution of chemicals in the media sampled. Consequently, there is significant uncertainty as to the actual levels present. Environmental chemistry analysis error can stem from several sources including the errors inherent in the analytical methods and characteristics of the matrix being sampled. In addition, there is uncertainty inherent in the measurement of radioactivity. Uncertainties in the exposure assessment are related to estimates of how often an individual would actually come in contact with the radionuclides of concern, the period of time over which such exposure would occur, and the models used to estimate the concentrations of the contaminants of concern at the point of exposure. Uncertainties in toxicological data occur in extrapolating both from animals to humans and from high to low doses of exposure, as well as from the difficulties in assessing the toxicity of a mixture of contaminants. These uncertainties are addressed by making conservative assumptions concerning risk and exposure parameters throughout the assessment. As a result, the Risk Assessment provides upper-bound estimates of the risks to populations that may be exposed to radionuclides, and is highly unlikely to underestimate actual risks related exposure. More specific information concerning public health risks, including a quantitative evaluation of the degree of risk associated with various exposure pathways, is presented in the Risk Assessment Report. Actual or threatened releases of hazardous substances from this Site, if not addressed by implementing the response action selected in this ROD, may present an imminent and substantial endangerment to public health, welfare, or the environment.

REMEDIAL ACTION OBJECTIVESRemedial action objectives are specific goals to protect human health and the environment. These objectives are based on available information and standards such as applicable or relevant and appropriate requirements (ARARs) and risk-based levels established in the risk assessment. EPAs remedial action objectives for the Welsbach/GGM. Contamination site are to take measures that will prevent or mitigate further release of radioactive contaminated materials to the surrounding environment and to eliminate or minimize the risk to human health and the environment. The sources of radiation include both contaminated soil and structural materials. Direct radiation, inhalation, ingestion of plants and soil are potential pathways. The following objectives were established for the Welsbach/GGM site: ! Eliminate or minimize the potential for humans to ingest, come into dermal contact with, or inhale particulates of radioactive constituents or to be exposed to external gamma radiation in order to achieve the level of protection required by the NCP (10-4 to 10-6 risk range).

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! ! ! ! !

Prevent long-term exposure to thorium- and radium-contaminated material (e.g., soil), with concentrations greater than 5 pCi/g. Prevent exposure to indoor concentrations of radon gas and radon decay product greater than 4 pCi/1 and 0.02 WL1, respectively. Prevent direct contact with building surfaces exhibiting total surface thorium contamination exceeding 0.026 Ci/m2 above background. Prevent migration of thorium-contaminated material that could result in the exposures described above. Comply with chemical-, location-, and action-specific ARARs.

EPA, in the Office of Solid Waste and Emergency Response (OSWER) Directives No. 9200.4-18 and No. 9200.4-25, developed health guidelines for limiting exposure to ionizing radiation from radium and other sources. To further ensure protectiveness, those health guidelines can be supplemented by selecting response actions which reduce exposures resulting from ionizing radiation to levels that are As Low As Reasonably Achievable (ALARA2) taking into consideration technical, economic and social factors. EPA recommends that indoor radon concentrations in homes should not exceed 4 pCi per liter of air (pCi/1). In 40 CFR 192, Standards for Cleanup of Land and Buildings Contaminated with Residual Radioactive Materials From Inactive Uranium Processing Sites, EPA enacted standards for limiting exposure to radon decay products and gamma radiation. While this regulation is not directly applicable to this site because the Welsbach and GGM Facilities are not inactive uranium processing sites. EPA considers the cleanup standards in 40 CFR 192 to be relevant and appropriate for the Site. The relevant portions of 40 CFR 192 include limiting exposure to: radon decay products to levels less than 0.02 WL and radium concentrations (implemented as the sum of Ra-226 and Ra-228) to 5 pCi/g. EPA, in Directive No.9200.4-25, states that whenever the 5 pCi/g radium soil cleanup standard is determined to be relevant and appropriate at a CERCLA site which contains both radium and thorium in-the waste, the pCi/g cleanup standard also applies to thorium, (implemented as the sum of Th-230 and Th-232). In achieving the remedial action objectives for the Site, EPA would rely on the ALARA principles used at other radiologically-contaminated sites in New Jersey. Applying ALARA

1

Exposure to 4 pCi/1 of air for radon corresponds to an approximate annual average exposure of 0.02 WL for radon decay products, when assuming residential land use. References for ALARA principles - Radiation Protection (Guidance to Federal, Agencies for Occupational Exposure. 1987, Federal Register 52. No. 17, 2822, and Federal Guidance Report No. 11", September 1988, EPA-520\1-88-020.2

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principles means taking additional measures during implementation of the remedial action, beyond those required to meet a specified cleanup goal, to assure protectiveness. An ALARA approach is being used because of the long-lived nature of radionuclides, the difficulty in eliminating routes of exposure, and limitations of the analytical equipment to detect radionuclides. EPAs experience at the other radiologically-contaminated sites in New Jersey has shown that the remedial action objectives noted above can be achieved by incorporating ALARA principles. Applying the 5 pCi/g cleanup standard with ALARA principles at these other New Jersey sites has resulted in exposure levels that are lower than the levels that would result from using the 5 pCi/g standard alone. Therefore, by using similar remedial action objectives, the Welsbach/GGM site would pose no unacceptable risk for residential uses after cleanup. and would result in a cleanup that is protective under CERCLA. The NJDEP has developed a draft proposed regulation concerning the remediation of radiologically-contaminated soil. In reviewing this case, the NJDEP believes that the remedy selected in this ROD will achieve the goals in the draft proposal through the incorporation of the ALARA principles in removing the radiologically-contaminated soils and covering the excavated areas with clean fill. The selected remedy will meet the remedial action objectives through the excavation and off-site disposal of the radiologically-contaminated soils and waste materials. Excavation of soils will eliminate the threat of physical migration of contaminants, as well as potential exposure through various pathways (ingestion, inhalation, dermal contact, external gamma radiation, etc.). Contaminated soils will be shipped off-site to a licensed commercial facility for permanent long-term management. For buildings, specifically at GGM, the selected remedy, decontamination. demolition, and off-site disposal of contaminated materials, will reduce exposures to acceptable levels for future use of the property. Any potential ecological risks and adverse impacts from existing radiological contamination on the properties addressed under this action will be minimized because the contaminated soils will be removed and backfilled with clean soil. There are also limited habitats for ecological receptors at the properties addressed under this action. Furthermore, by removing the radiologically-contaminated waste, the surface water and sheet flow pathways will be eliminated as routes of exposure. Wetlands are not present at either the former Welsbach or GGM facilities. However, wetlands are present in Areas 3 and 5, along the South Branch of Newton Creek. During the remedial design, EPA will delineate wetland areas which are actually or potentially impacted by contamination or remedial activities.

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DESCRIPTION OF REMEDIAL ALTERNATIVESSection 121(b)(1) of CERCLA, 42 U.S.C. 9621(b)(1), mandates that a remedial action must be protective of human health and the environment. cost-effective, and utilize permanent solutions and alternative treatment technologies or resource recovery technologies to the maximum extent practicable. Section 121(b)(1) also establishes a preference for remedial actions which employ, as a principal element, treatment which permanently and significantly reduces the volume, toxicity, or mobility of the hazardous substances, pollutants and contaminants at a site. Section 121(d) of CERCLA, 42 U.S.C. 9621(d), further specifies that a remedial action must attain a level or standard of control of the hazardous substances, pollutants, and contaminants, which at least attains ARARs under federal and state laws, unless a waiver can be justified pursuant to Section 121(d)(4) of CERCLA, 42U.S.C. 9621(d)(4). CERCLA also requires that if a remedial action is selected that results in hazardous substances, pollutants, or contaminants remaining at a site above levels that allow for unlimited use and unrestricted exposure, EPA must review the action no less than every five years after the start of the action. In the RI/FS Report, EPA evaluated Remedial Alternatives for addressing the radiological contamination associated with the Site. Cleanup alternatives were evacuated for the Vicinity Properties, the former Welsbach Facility and the General Gas Mantle Facility. The alternatives include: No Action, Engineering Controls, and Excavation and Off-Site Disposal. Table 8 summarizes the costs of each alternative. Vicinity Properties The Vicinity Properties include residential, commercial, and public properties where radiological contamination was identified in soils located outdoors and/or beneath buildings, and properties with indoor air contamination. Vicinity Properties Alternative 1 (V-1) - No Action Estimated Capital Cost: Estimated Annual Operation and Maintenance (O&M) Cost: Estimated Present Worth: Estimated Implementation Period: $0 $0 $0 none

A No Action alternative is evaluated for every Superfund site to establish a baseline for comparison with remedial alternatives. Under this alternative, no remedial action would be performed at the Site. Previous interim remedial actions implemented by NJDEP would not be maintained. Current institutional controls including fencing would not be maintained. Because hazardous substances would remain at the Vicinity Properties above acceptable levels, five-year reviews would be required.

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Vicinity Properties Alternative 2 (V-2) - Engineering Controls Estimated Capital Cost: Estimated Annual O&M Cost: Estimated Present Worth: Estimated Implementation Period: $900,000 $99,000 $1,810,000 3-5 years

Under this alternative, outdoor gamma shielding would be placed at each property which has contaminated soil. The gamma shield would consist of a geotextile liner, fill material, 6 inches of topsoil, and vegetation (seeding or sod). The thickness of the fill material will vary from 6 inches to 42 inches, based on the shielding requirements of each property. A total of approximately 75,000 square feet of coverage would be installed. In addition, indoor gamma shielding would be placed inside buildings exhibiting unacceptable exposure levels. The shielding would consist of concrete or steel as needed. The concrete would range from 4 inches to 7 inches thick, and about 1.5 inches of steel sheeting would be placed on wall surfaces. A total of approximately 2,000 square feet of concrete and 60 square feet of steel coverage would be installed. Finally, if any property buildings exhibit elevated radon/thoron levels, a sub-slab ventilation radon mitigation system would be installed. Institutional controls, such as deed restrictions, would be required to ensure the protectiveness of the remedy. Because hazardous substances would remain at the Vicinity Properties above acceptable levels, five-year reviews would be required. The estimated time to design and construct the remedy is from three to five years. Vicinity Properties Alternative 3 (V-3) - Excavation and Off-Site Disposal Estimated Capital Cost: Estimated Annual O&M Cost: Estimated Present Worth: Estimated Implementation Period: $13,408,560 $0 $13,408,560 3-5 years

Under this alternative, soil on the Vicinity Properties contaminated above 5 pCi/g greater than background would be excavated and disposed of at a licensed off-site facility. Radiologicallycontaminated building demolition debris would also be excavated and disposed of off-site. EPA will replace these areas with clean fill. The total volume of soils requiring disposal at the Vicinity Properties is estimated to be 11,000 cubic yards. The total volume of buried demolition debris at the Vicinity Properties is estimated to be 2,250 cubic yards. Where contamination is suspected underneath buildings, this alternative includes removing concrete flooring and underpinning the buildings. After the removal of contaminated soil, a new concrete floor would be constructed. Approximately 21 properties would require concrete floor removal and replacement. Underpinning may be required at one property.17

The estimated time to design and construct the remedy is three to five years. Provisions would need to be made for the temporary relocation of residents and businesses during construction of this alternative. During excavation. short-term provisions to prevent dust generation and protect workers would be required. EPA will develop a wetland mitigation plan if it disturbs wetland areas by remedial activities. Welsbach Facility The former Welsbach Facility is presently owned and operated by Holt as a cargo storage and oversea shipping operation. Radiological contamination on the property is present in the outdoor portion of the storage area. Most of the contamination is located in a single contiguous area. with smaller contaminated areas scattered across the property. The Armstrong Building is not included in the remediation alternatives. Holt is preparing an RI/FS that will address the remedial alternatives for that building. Welsbach Alternative I (W-1) - No Action Estimated Capital Cost: Estimated Annual O&M Cost: Estimated Present Worth: Estimated Implementation Period: $0 $0 $0 none

Under this alternative, no remedial action would be performed at the Site. Current institutional controls, including fencing, would not be maintained. Because hazardous substances would remain on the property above acceptable levels. five-year reviews would be required. Welsbach Alternative 2 (W-2) - Engineering Controls Estimated Capital Cost: Estimated Annual O&M Cost: Estimated Present Worth: Estimated Implementation Period: $5,686,000 $44,000 $6,182,000 3-5 years

Under this alternative, outdoor gamma shielding would be placed in the areas of the former Welsbach property that have soil contamination. The gamma shield would consist of steel covered by asphalt. The steel would range in thickness from 1 to 5 inches, with a 4-incn asphalt cover. Approximately 53,000 square feet of area would be, covered by the steel shielding. Institutional controls, such as deed restrictions, would be required to ensure the protectiveness of the remedy. Because hazardous substances would remain on the property above acceptable levels, five-year reviews would be required. The estimated time to design and construct the remedy is three to five years.18

Welsbach Alternative 3 (W-3) - Excavation and Off-Site Disposal Estimated Capital Cost: Estimated Annual O&M Cost: Estimated Present Worth: Estimated Implementation Period: $18,503,560 $0 $18.503.560 3-5 years

Under this alternative, all soil contamination at the Welsbach site above 5 pCi/g greater than background would be excavated and disposed of at a licensed off-site facility. EPA will also excavate contaminated building debris from past demolition activities, which is currently buried on-site, and dispose of this material at an appropriate off-site facility. EPA will backfill these areas with clean fill. The volume of soils above the cleanup standard is estimated to be 19,400 cubic yards. The volume of buried demolition debris requiring disposal is estimated to be 4.400 cubic yards. During excavation, short-term provisions to prevent dust generation and protect workers would be required. Subsurface contamination on the Welsbach Facility averages about 11 feet in depth. In the area of the deepest contamination, underground tunnels dating from around the turn of the century are present. These tunnels extend down to about 10 to 12 feet in depth. These tunnels can act as conduits to carry radon gas to nearby residential properties. As a result, the remedy includes excavation of the contamination to the tunnel depths to prevent any future radon migration problems and to protect future workers from elevated gamma radiation levels. The estimated time to design and construct the remedy is three to five years. General Gas Mantle Facility The GGM building is presently inactive and in a dilapidated state. The building has been boarded shut and fenced in by NJDEP. Radiological contamination on the property exists both inside and outside the building. Inside the building, contamination is present in building materials and in ambient air. Outside the GGM Facility, soil contamination is primarily located to the inunediate southwest of the GGM building extending into South Fourth Street. Two smaller areas of contaminated soils are situated to the northeast of the building and in the alleyway adjacent to the eastern side of the building. General Gas Mantle Alternative 1 (G-1) - No Action Estimated Capital Cost: Estimated Annual O&M Cost: Estimated Present Worth: Estimated Implementation Period: $0 $0 $0 none

Under this alternative, no remedial action would be performed at the Site. PTevious interim remedial actions would not be maintained. Current institutional controls including fencing would19

not be maintained. Because hazardous substances would remain on the property above acceptable levels, five-year reviews would be required. General Gas Mantle Alternative 2 (G - 2) - Engineering Controls Estimated Capital Cost: Estimated Annual O&M Cost: Estimated Present Worth: Estimated Implementation Period: $122.000 $23.000 $381.000 2-3 years

Under this alternative, outdoor gamma shielding would be placed at the former General Gas Mantle property. The gamma shield would consist of either a soil shield or a concrete shield. The soil shield would include a geotextile liner, fill material, 6 inches of tonsoil, and vegetation (seeding or sod). The thickness of the fill material will range, from 6 to 24 inches. The thickness of the concrete will range from 6 to 8 inches. Approyimately 5,000 square feet of coverage would be required. Areas of contamination extending into Forth Fourth Street would be covered with an additional 4 inches of asphalt. Also under this alternative, significant institutional controls, including permanently boarding shut the building and restricting access to the building forever, would be required. Because hazardous substances would remain on the property above acceptable levels, five-year reviews would be required. The estimated time to design and construct the remedy is two to three years. General Gas Mantle Alternative 3 - Excavation and Off-Site Disposal of Soil and Building/Demolition Debris Option A: Demolition and Disposal Estimated Capital Cost: Estimated Annual O&M Cost: Estimated Present Worth: Estimated Implementation Period: $2,309,560 $0 $2,309,560 1-2 years

Under this alternative for the GGM property, EPA will excavate contaminated soil above 5 pCi/g greater than background and dispose of this waste in a licensed off-site facility. Contaminated building demolition debris which is currently buried on-site because of former demolition activities would also be excavated and disposed of off-site. EPA will backfill these areas with clean fill. The volume of soil and buried dem6lition debris at GGM is estimated to be 650 cubic yards and 60 cubic yards, respectively. Under this alternative, the former General Gas Mantle building would be demolished, and the demolition debris would be disposed of with the contaminated soil. The volume of building materials to be demolished is estimated to be 1,400 cubic yards. During excavation and20

demolition, short-term provisions to prevent dust generation and protect workers would be required. The estimated time to design and construct the remedy is one to two years. Option B: Decontamination, Demolition and Disposal Estimated Capital Cost: Estimated Annual O&M Cost: Estimated Present Worth: Estimated Implementation Period: $1.979.560 $0 $1.979.560 1-2 years

This alternative essentially would be the same as 3A above, except that the demolition of the building would proceed in steps. First, the wood structural materials and roofing would be removed. This debris (approximately 450 cubic yards) would be disposed of with the contaminated soil. The remainder of the building (approximately 950 cubic yards of primarily masonry and concrete) would then be decontaminated using pressure washing before demolition. The contaminated waste water would be disposed of at an approved off-site facility. The building would then be demolished and the debris would be crushed and sent off-site for disposal. The estimated time to design and construct the remedy is one to two years. SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES In selecting a remedy, EPA considered the factors set out in Section 121 of CERCLA, 42 U.S.C. 9621, by conducting a detailed analysis of the viable remedial alternatives pursuant to the NCP, 40 CFR 300.430(e)(9) and OSWER Directive 9355.3-01. The detailed analysis consisted of an assessment of the individual alternatives against each of nine evaluation criteria and a comparative analysis focusing upon the relative performance of each alternative against those criteria. The following threshold criteria are the most important and must be satisfied by any alternative in order to be eligible for selection: 1. Overall protection of human health and the environment considers whether or not a remedial alternative provides adequate protection and describes how risks posed through each exposure pathway are eliminated, reduced, or controlled through treatment, engineering controls, or institutional controls. Compliance with ARARs addresses whether or not a remedial alternative meets all of the applicable or relevant and appropriate requirements of federal and state environmental statutes and requirements, or provides grounds for invoking a waiver.

2.

The following primary balancing criteria are used to make comparisons and to identify the major trade-offs between alternatives:21

3.

Long-term effectiveness and permanence, refers to the ability of a remedial alternative to maintain reliable protection of human health and the environment over time, once cleanup goals have been met. It also addresses that magnitude and effectiveness of the measures that may be required to manage the risk based by treatment residuals and/or untreated wastes. Reduction of toxicity, mobility, or volume through treatment addresses the statutory preference for selecting remedial actions that employ treatment technologies that permanently and significantly reduce toxicity, mobility, or volume of hazardous substances as a principal element. Short-term effectiveness considers the period of time needed to achieve protection and any adverse impacts on human health and the environment that may be posed during the construction and implementation period until cleanup goals are achieved. Implementability refers to the technical and administrative feasibility of a remedial alternative, including the availability of materials and services needed to implement the alternative. Cost includes the estimated capital and operation and maintenance costs, and the present- worth costs.

4.

5.

6.

7.

The following modifying criteria are considerea ;ully after the formal public cornment period on the Proposed Plan is complete: 8. State acceptance indicates whether, based on its review of the RI/FS reports and the Proposed Plan, the State supports, opposes, and/or has identified any reservations with the preferred alternative. Community acceptance refers to the publics general response to the alternatives described in the Proposed Plan and tne RI/FS report. Responses to public comments are addressed in the Responsiveness Summary section of this Record of Decision.

9.

A comparative analysis of the remedial alternatives based upon the evaluation criteria noted above follows: Overall Protection to Human Health and the Environment The No Action Alternatives (W-1, V-1, G-1) would not be protective of human health and the environment because the Site would remain in its current contaminated condition. Therefore, the No Action Alternatives have been eliminated from consideration and will not be discussed further.

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Under the Engineering Controls Alternatives (W-2, V-2. G-2), potential exposure routes of gamma radiation would be shielded by soil, concrete and/or steel sheeting. The shielding would have to be maintained, and institutional controls, such as deed restrictions, would be required to ensure that these alternatives are protective. For the Excavation and Off-Site Disposal Alternatives (W-3, V-3, G-3). all radiological contamination above cleanup standards would be excavated and disposed of off-site in a licensed disposal facility. Institutional controls would not be necessary. All unacceptable risks to human health and the environment would be eliminated by the excavation and off-site disposal of the radiologically-contaminated waste. Compliance with Applicable or Relevant. and Appropriate Requirements Actions taken at any Superfund site must meet all ARARs of federal and state law, or provide grounds for invoking a waiver of these requirements. There are three types of ARARs: actionspecific, chemical-specific, and location-specific. Action-specific ARARs are technology or activity-specific requirements or limitations related to various activities. Chemical-specific ARARs are usually numerical values which establish the amount or concentration of a chemical that may be found in, or discharged to, the ambient environment. Location-specific requirements are restrictions placed on the concentrations of hazardous substances or the conduct of activities solely because they occur in a special location. For the Welsbach/GGM site, no requirements are applicable for the cleanup of the radiological contamination. However, as discussed earlier, portions of the federal regulations governing the cleanup of uranium mill tailings from inactive uranium processing sites, at 40 CFR 192, have been determined to be relevant and appropriate. These provide the radon decay products standard of 0.02 WL and soil cleanup criteria of 5 pCi/g above background. The Excavation and Off-Site Disposal Alternatives (W-3, V-3, G-3) would comply with all ARARs. All contamination above the 40 CFR 192 cleanup standards would be excavated and sent off-site for disposal. The Engineering Controls Alternatives (W-2, V-2, G-2) would comply with all ARARs that limit exposure to gamma radiation and radon. However, the Engineering Controls Alternatives would not comply with 40 CFR 192, because the contaminated material would remain at the Site. Long-Term Effectiveness and Permanence The Excavation and Off-Site Disposal Alternatives (W-3, V-3, G-3) are all effective and permanent. They are considered a final remedial action. The contaminated material would be removed from the Site and stored in a controlled, licensed off-site facility. The long-term effectiveness of the Engineering Controls Alternatives W-2 and V-2 would be uncertain. Contaminated material would remain in place, and the engineering controls would 23

require deed restrictions and long-term monitoring. In addition. the engineering controls would have to be maintained forever because the half-life of thorium. is 14 billion years. Alternative G-2 (Engineering Controls for General Gas Mantle) would not be effective in the long-term because of the dilapidated nature of the building, even if the building were completely sealed. Reduction of Toxicity, Mobility, or Volume Through Treatment No treatment technology is known today that can substantially reduce the toxicity, mobility, or volume of radioactive materials found at the Site, and meet the 40 CFR 192 cleanup standards. The total amount of radioactivity cannot be altered or destroyed, as is often possible with chemical contaminants. Therefore, none of the remedial alternatives fully satisfy this evaluation criteria. However, Alternative G-3 with Option B (the General Gas Mantle Decontamination and Demolition Alternative) would reduce the volume of contaminated building debris to be disposed of off-site by pressure washing the radioactive contamination off the floors and walls before demolition. The contaminants would be concentrated in the filtrate after pressure washing. Only this filtrate would have to be disposed of in a licensed off-site facility. Short-Term-Effectiveness Both the Engineering Control Alternatives (W-2, V-2, G-2) and the Excavation and Off-Site Disposal Alternatives (W-3, V-3, G-3) provide effective short-term protection, and become effective as they are implemented at individual properties. The estimated time to design and construct the remedial alternatives for the former Welsbach Facility (Alternatives W-2 and W-3) and the Vicinity Properties (Alternatives V-2 and V-3) is from three to five years. For the former GGM Facility, the estimated time to design and construct the Engineering Control Alternative G-2 is from two to three years, and for the Excavation and Off-Site Disposal Alternative G-3 from one to two years. The Engineering Control Alternatives involve less intrusive activities, and pose less of a threat to workers and the surrounding community than the Excavation and Off-Site Disposal Alternatives. However, both the Engineering Control Alternatives and the Excavation and Off-Site Disposal Alternatives involve intrusive activities, including, in some cases, temporary relocation of residents. The Excavation and Off-Site Disposal Alternatives have a greater potential adverse impact in the short term because of the excavation of radiologically-contaminated soil. For future workers, this could lead to increased short-term exposure to radon, gamma radiation, and soil radionuclides. Dust suppression techniques and/or other measures would be required to minimize the impacts of this alternative. However, under Alternative V-2 (Engineering Controls for the Vicinity 24

Properties), there would be some increased short-term risk to workers during the installation of the radon mitigation systems. This is due to the need to excavate under the foundation of homes that require radon mitigation. Implementability The Excavation and Off-Site Disposal Alternatives (W-3, V-3 and G-3) are readily implementable. Similar activities have been utilized at other radiologically-contaminated sites around the country. There is an available off-site disposal facility. which is accessible by both truck and rail. However, the continued availability of this off-site disposal facility is required for implementation of these alternatives. Implementation of the Engineering Controls Alternatives V-2 and G-2 may pose some difficulties. Under Alternative V-2 (for the Vicinity Properties), there may be some difficulty in getting the consent of all of the property owners to restrict future work on their properties. EPA would have to reach agreement with individual property owners to file Declarations of Environmental Restrictions (i.e., deed restrictions) on their properties. For Alternative G-2 (for General Gas Mantle), it would be difficult to keep the building permanently sealed from trespassers. Cost Alternative V-2 includes construction costs of $900,000 to implement engineering control measures at the Vicinity Properties. Annual O&M costs are estimated to be $99,000. The present worth cost of Alternative V-2 is $1,810,000, with O&M costs assumed for 30 years. Alternative W-2 includes construction costs of $5,686,000 to implement engineering control measures at the former Welsbach Facility. Annual O&M costs are estimated to be $44,000. The present worth cost of Alternative W-2 is $6,182,000, with O&M costs assumed for 30 years. Alternative G-2 includes construction costs of $122,000 to implement engineering controls at the General Gas Mantle Facility. Annual O&M costs are estimated to be $23,000. The present worth cost of Alternative G-2 is $381,000, with O&M costs assumed for 30 years. The radionuclides in question have half-lives far greater than 30 years, so any of the Engineering Controls remedies must be maintained effectively forever. Alternative V-3 includes construction costs of $13,408,560 to excavate the radiologically contaminated soil at the Vicinity Properties and dispose of the waste at an off-site disposal facility. Alternative W-3 includes construction costs of $18,503,560 to excavate the radiologically-contaminated soil at the former Welsbach Facility and dispose of the waste at an off-site disposal facility. Alternative G-3 - Option A involves construction costs of $2,309,560, and includes demolishing the General Gas Mantle building and disposal of all the building debris at an off-site disposal facility Alternative G-3 - Option B involves construction costs of $1,979,560, and includes decontaminating the General Gas Mantle building before its demolition.

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There are no O&M costs associated with the Excavation and Off-Site Disposal Altematives W-3, V-3 and G-3 Options A and B). State Acceptance The State concurs with the selected remedial action. Community Acceptance EPA solicited input from the community on the remedial alternatives proposed for the Welsbach/General Gas Mantle Contamination Site. The community was supportive of EPAs preferred remedy which called for the excavation and off-site disposal of the radiologically contaminated soils at the Site. The No Action and Engineering Controls Alternatives received no community support. The attached Responsiveness Summary addresses the comments received during the public comment period. SELECTED REMEDY Based upon consideration of the results of the RI/FS, the requirements of CERCLA, the detailed analysis of the alternatives, and public comments, EPA and NJDEP have determined that the Excavation and Off-Site Disposal Alternatives (V-3, W-3, and G-3 with Option B) are the appropriate remedies for the Site. The selected remedial action will provide a final remedy and achieve the remedial action objectives at the Vicinity Properties and the Welsbach and General Gas Mantle Facilities by: ! eliminating or minimizing the potential for humans to ingest, come in dermal contact with, or inhale particulates of radioactive constituents, or be exposed to external gamma radiation, thereby achieving the level of protection required by the NCP; preventing exposure to radon gas and radon decay products in excess of 4 pCi/L and 0.02 WL, respectively; preventing direct contact with building surfaces exhibiting total surface thorium contamination exceeding 0.026 Ci/m2 above background; preventing long-term exposure to thorium- and radium-contaminated materials with concentrations greater than 5 pCi/g above background; and preventing migration of radiologically-contaminated materials that could result in exposures described above.

! ! ! !

26

Radiologically-contaminated soil found on the Vicinity Properties and the former Welsbach and GGM Facilities in excess of 5 pCi/g above background will be excavated consistent with 40 CFR 192, Subparts B and E. The remedy will attain a risk level similar to risk levels associated with exposure to natural background radiation. This will be confirmed via post-excavation property surveys. The Multi-Agency Radiation Survey and Site Investigation Manual (MARISSM) may be used where appropriate to conduct such property surveys. MARISSM provides a methodology to confirm that a particular soil concentration level has been achieved after the remedial action is completed. An appropriate survey methodology to be used will be determined during remedial design. EPA estimates that the following volumes of contaminated soil and debris will be removed from the Site: Vicinity Properties - 13,000 cubic yards, General Gas Mantle - 2.500 cubic yards. Welsbach Facility - 27,000 cubic yards. EPA will dispose of the radiologically-contaminated material at a licensed, off-site facility. Areas that have been excavated will be restored with clean fill. No significant changes in land use are anticipated. Because all contamination above the cleanup criteria will be excavated and sent off-site for disposal, all remediated properties will be available for unrestricted future use. EPA will make every effort to minimize any long-term disruption to individual residents or the community. During excavation, EPA may need to temporarily relocate some residents at government expense. As previously stated, EPA will investigate approximately 600 Suspect Properties during the remedial design phase. When these properties are tested, it is likely that some will be found to contain radiologically-contaminated material and will require remediation. The selected remedy also includes such remediation. EPA believes that cleanup of additional contaminated properties will not affect the overall scope of the remedial action. STATUTORY DETERMINATIONS Superfund remedy selection is based on CERCLA and the regulations contained in the NCP. Under its legal authorities, EPAs primary responsibility in selecting remedies at Superfund sites is to undertake actions that are protective of human health and the environment. In addition, Section 121 of CERCLA establishes several other statutory requirements and preferences. These specify that, when complete, the selected remedial action for this site must comply with applicable or relevant and appropriate environmental standards established under federal and state environmental laws unless a statutory waiver is justified. The selected remedy also must be cost effective and utilize permanent solutions and alternative treatment technologies or resource recovery technologies to the maximum extent practicable. Finally, the statute includes a preference for remedies that employ treatment that permanently and significantly reduce the volume, toxicity, or mobility of the hazardous wastes, as their principal element. The following sections discuss how the selected remedy meets these statutory requirements for the first operable unit of the Welsbach/GGM site. 27

Protection of Human Health and the Environment This remedy is fully protective of human health and the environment for all properties, with radiological contamination above the cleanup standards. It is estimated that no radiologicallycontaminated soil above the cleanup standards will remain on the affected properties. The remedy will attain a risk level similar to risk levels associated with exposure to natural background radiation. Implementation of this remedy will eliminate additional risks attributable to exposures to indoor or outdoor gamma radiation, indoor radon gas or radon decay products, inhalation and/or ingestion of contaminated soil, and ingestion of contaminated vegetables grown in contaminated soil. This remedy will comply with the ARARs for exposure to indoor gamma radiation and the inhalation of radon gas or radon decay products, and attainment of soil cleanup standards. There are few short-term risks associated with the implementation of this remedy. Where excavation occurs, dust suppression measures can reduce the risk of inhalation of radiologicallycontaminated dust. In addition, no adverse cross-media impacts are expected from the remedy. Compliance with ARARs As presented earlier, the primary ARARs for this site are contained in 40 CFR 192, Subpart B. This regulation deals with the cleanup of inactive uranium processing facilities. EPA has determined that while these standards are not applicable, they are relevant and appropriate to the situation at the Welsbach/GGM site. Table 9 lists and summarizes these and other standards that may be pertinent during the implementation of this remedial action. When implemented, the cleanup of the affected properties within the study areas will comply with all public health and soil cleanup ARARs, and will allow for unrestricted use of these properties. Cost Effectiveness The selected remedy is cost-effective because it provides the highest degree of overall effectiveness relative to its cost. The remedy provides for complete protection of public health and the environment at the affected properties. The radioactive half-life of thorium-232, the primary contaminant of concern, is 14 billion years. Remedies that would isolate wastes containing thorium and the uranium series radionuclides permanently from the public and the environment are preferable. Utilization of Permanent Solutions and Alternative Treatment Technologies to thq Maximum Extent Practicable EPA and the State of New Jersey have determined that the selected remedy represents the maximum extent to which permanent solutions and currently available treatment technologies can 28

be utilized in a cost-effective manner for this phase of the remedial action at the Welsbach/General Gas Mantle Contamination site. Of those alternatives that are protective of human health and the environment and comply with ARARs, EPA and the State of New Jersey have determined that the selected remedy provides the best balance of trade-offs in terms of long-term effectiveness and permanence, short-term effectiveness, implementability, cost, the statutory preference for treatment as a principal element and State and community acceptance. Alternatives V-3, W-3, and G-3 result in a permanent solution to the radioactive contamination. The longevity of these contaminants of concern (thousands to billions of years) favors excavation which permanently removes them from their current uncontrolled locations. Commercial disposal at a licensed facility with an appropriate closure plan will ensure that these radiological wastes are permanently isolated from human and ecological receptors. The Excavation and Off-Site Disposal Alternatives are considered implementable and will result in a remedy that is highly effective in the long-term. These remedies are also consistent with the remedial approach taken at all other radiologically-contaminated sites in New Jersey. Preference for Treatment as a Principal Element The principal threat at the Site is from exposure to excess levels of indoor and/or outdoor gamma radiation, and ingestion and/or inhalation of radiologically-contaminated soil. In addition, there are threats from the generation of excess concentrations of radon gas and radon decay products indoors which migrate from the underlying soils, and are subsequently inhaled by the residents of those houses. Because there is no treatment available that destroys the radioactive source of these threats, the selected remedy does not satisfy the statutory preference for treatment as the principal element. The remedy does reduce the exposure to all excess levels of indoor and/or outdoor gamma radiation. It also provides for complete remediation at the affected properties, thereby reducing the exposure risk from all pathways. DOCUMENTATION OF SIGNIFICANT CHANGES There are no significant changes from the preferred alternative presented in the Proposed Plan.

29

APPENDIX I FIGURES

30

31

32

APPENDIX II TABLES

34

TABLE -1 RADIATION UNITSHistorical Parameter Unit Quantity Radionuclide Concentration in Soil or Other Solid Material Radionuclide Concentration in Water Radon Gas Conc. Radon Progeny Conc. Exposure Rate Dose Dose Equivalent Curie picoCurie per gram of Solid Abbrev. Ci pCi/g Unit Becquerel Becquerel per kilogram Abbrev. Bq Bq/kg International

picoCurie per liter of Water picoCurie per liter of Air Working Level micro-Roentgen per hour Radiation Absorbed Dose Radiation Equivalent Man

pCi/L

---

pCi/L WL R/h rad rem

Becquerel per cu. meter -- Gray Sievert

Bq/m3 --

Gy Sv

35

TABLE-2 PROPERTY CHARACTERIZATION WELSBACII/GGM SITESTUDY AREA PROPERTIES SURVERYED BY THE NJDEP PROPERTIES WITH NO EVIDENCE OF CONTAMINATION 4.0 pCi/L RADON Note:1

AREA 1 359 103

AREA 2 174 40

AREA 3 48 18

AREA 4 474 272

AREA 5 32 16

AREA 6 NA1 0

TOTAL 1088 449

239

113

23

199

11

0

585

17

21

7

3

5

1

54

- Study Area 6 was not part of the NJDEP investigation.

NA - Not Applicable

36

TABLE 3 ESTIMATED VOLUME OF CONTAMINATED MATERIALS WELSBACH/GGM SITE SOIL (CUBIC YARDS) STRUCTURAL/DEBRIS MATERIALS (CUBIC YARDS) 5,000

FORMER WELSBACH FACILITY FORMER GGM FACILITY

22,200

885

1,460

VICINITY PROPERTIES

11,010

2,255

TOTAL

34,100

8,720

37

TABLE 4 RADIOLOGICAL RISK ESTIMATES BASED ON REASONABLE MAXIMUM EXPOSURES AT FORMER GAS MANTLE MANUFACTURING FACILITIES

POPULATION

PATHWAY

EXPOSURE MEDIUM

GROSS RISK

BACKGROUND RISK

NET RISK

TOTAL RISK

FORMER WELSBACH FACILITYWORKER OTHER WORKER CONSTRUCTION WORKER EXTERNAL EXTERNAL EXTERNAL INGESTION INHALATION SOIL SOIL SOIL SOIL PARTICULATES 5.70e-02 1.40e-02 7.50e-04 3.10e-05 1.10e-03 7.30e-05 1.80e-05 8.70e-07 5.60e-08 8.40e-07 5.70e-02 1.40e-02 7.50e-04 3.10e-05 1.10e-03 5.70e-02 1.40e-02

1.90e-03

FORMER GENERAL GAS MANTLE FACILITYTRESPASSER EXTERNAL * INGESTION INHALATION * EXTERNAL INGESTION INHALATION EXTERNAL INGESTION * INHALATION EXTERNAL INGESTION * INHALATION EXTERNAL INHALATION * SOIL BUILDING MATERIALS SOIL PARTICULATES RADON DECAY PRODUCTS SOIL SOIL PARTICULATES SOIL SOIL HOME GROWN PRODUCE RADON DECAY PRODUCTS SOIL SOIL HOME GROWN PRODUCE RADON DECAY PRODUCTS BUILDING MATERIALS PARTICULATES RADON DECAY PRODUCTS 3.10e-05 2.00e-05 1.90e-06 0.00e+00 2.50e-03 2.10e-05 7.50e-07 2.80e-05 8.90e-03 2.70e-05 2.30e-08 4.90e-03 1.80e-03 1.10e-05 1.90e-06 5.60e-04 1.40e-03 0.00e+00 1.80e-01 1.30e-06 3.40e-06 1.40e-07 0.00e+00 7.40e-06 8.70e-07 5.60e-08 8.40e-07 3.80e-04 2.00e-06 3.20e-06 8.00e-04 7.80e-05 8.10e-07 2.70e-07 9.20e-05 2.40e-04 0.00e+00 5.10e-04 3.00e-06 1.70e-05 1.80e-06 0.00e+00 2.50e-03 2.00e-05 6.90e-07 2.70e-05 8.50e-03 2.50e-05 2.00e-05 4.10e-03 1.70e-03 1.00e-05 1.60e-06 4.70e-04 1.20e-03 0.00e+00 1.80e-01

2.50e-03

CONSTRUCTION WORKER

4.80e-05

ADULT RESIDENT

1.30e-02

CHILD RESIDENT

2.20e-03

WORKER

1.80e-01

38

TABLE 5 VICINITY PROPERTIES SUMMARY OF RADIOLOGICAL RISK ESTIMATES BASED ON REASONABLE MAXIMUM EXPOSURES*RISK VICINITY PROPERTY POPULATION PATHWAY GROSS BACKGROUND NET

SITE WORKER PUBLIC PARK

External Inhalation of Particulates Inhalation of Radon Ingestion of Soil Total: EXTERNAL Inhalation of Particulates Ingestion of Soil Total: External Inhalation of Particulates Ingestion of Soil Total: External Inhalation of Radon Ingestion of Soil Total:

7.3e-01 2.3e-02 1.7e-03 3.0e-03 7.6e-01 3.3e-04 1.1e-05 1.1e-06 3.4e-04 2.2e-01 6.9e-03 4.5e-04 2.3e-01 4.7e-02 1.2e-01 1.2e-04 1.7e-01 4.4e-02 1.2e-03 1.8e-04 4.5e-02 7.0e-02 2.5e-02 2.5e-03 4.6e-04 9.8e-02 2.4e-03 1.2e-04 2.3e-06 2.5e-03

8.6e-05 1.8e-06 5.2e-04 5.5e-07 6.1e-04 8.3e-07 3.1e-08 3.1e-09 8.6e-0 2.6e-05 5.5e-07 8.3e-08 2.7e-05 3.5e-04 7.9e-04 2.0e-06 1.1e-03 5.1e-06 9.4e-08 3.3e-08 5.2e-06 6.8e-05 9.0e-05 3.8e-06 7.8e-07 1.6e-04 2.5e-06 9.4e-08 3.8e-09 2.6e-06

7.3e-01 2.3e-02 1.2e-03 3.0e-03 7.6e-01 3.3e-04 1.1e-05 1.1e-06 3.4e-04 2.2e-01 6.9e-03 4.5e-04 2.3e-01 4.7e-02 1.2e-01 1.2e-04 1.7e-01 4.4e-02 1.2e-03 1.8e-04 4.5e-02 7.0e-02 2.5e-02 2.5e-03 4.6e-04 9.8e-02 2.4e-03 1.2e-04 2.3e-06 2.5e-03

POPCORN FACTORY

CONSTRUCTION WORKER

PUBLIC PARK

ADULT RECREATIONALIST

POPCORN FACTORY

RESIDENT ADULT

PUBLIC PARK

CHILD RECREATIONALIST

Eternal Inhalation of Particulates Ingestion of Soil Total: External Inhalation of Radon Ingestion of Home Grown Produce Ingestion of Soil Total: Eternal Inhalation of Particulates Ingestion of Soil Total:

RESIDENT CHILD LAND PRESERVE

LAND PRESERVE

TRESPASSER

The exposure duration varies for each population considered in the risk Assessment. Only the maximum risk estimates for each population evaluated are provided.

39

TABLE 6 RISK ASSESSMENT SUMMARY FORMER WELSBACH FACILITYScenario Timeframe: Future Receptor Population: Construction Worker Receptor Age: Adult

Carcinogenic Risk Medium Exposure Chemical Ingestion Inhalation Dermal Exposure Routes Total 6e-08 1e-07 6e-07 2e-08 2e-08 -8e-06 -8e-06 ---2e-09 2e-09 -1e-05 -1e-05 2e-05 2e-05 (Total) (Total)

Non-Carcinogenic

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