Benzene Exposures from Petroleum Benzene Exposures from Petroleum - - Derived Solvents Containing Trace Derived Solvents Containing Trace Levels of Benzene in Occupational Levels of Benzene in Occupational Settings Settings P. Williams, J. Panko, K. Unice, J. Brown, and D. Paustenbach P. Williams, J. Panko, K. Unice, J. Brown, and D. Paustenbach Presented by: Presented by: Julie Panko, CIH Julie Panko, CIH Chem Chem Risk Risk , Inc. , Inc. [email protected][email protected]AIHCE Philadelphia, PA June 7, 2007
Transcript
Benzene Exposures from PetroleumBenzene Exposures from Petroleum--Derived Solvents Containing Trace Derived Solvents Containing Trace Levels of Benzene in Occupational Levels of Benzene in Occupational
SettingsSettingsP. Williams, J. Panko, K. Unice, J. Brown, and D. PaustenbachP. Williams, J. Panko, K. Unice, J. Brown, and D. Paustenbach
Presented by:Presented by:Julie Panko, CIHJulie Panko, CIHChemChemRiskRisk, Inc., Inc.
BackgroundBackgroundSeveral thousand lawsuits have been filed alleging a Several thousand lawsuits have been filed alleging a relationship between use of a petroleum based product relationship between use of a petroleum based product and various illnesses due to benzene exposure.and various illnesses due to benzene exposure.The theory is that use of products that contain less than The theory is that use of products that contain less than 0.1% benzene can result in exposures greater than the 0.1% benzene can result in exposures greater than the TLV or PEL.TLV or PEL.The possibility for such an occurrence has been The possibility for such an occurrence has been reported in the literature recently.reported in the literature recently.
FedorukFedoruk et al. 2003 et al. 2003 KopsteinKopstein 20062006NicasNicas et al. 2006et al. 2006
ObjectiveObjective
Discuss the benzene content and flammability Discuss the benzene content and flammability hazard of petroleumhazard of petroleum--derived products, which are derived products, which are important for understanding the typical and safe important for understanding the typical and safe uses of these products uses of these products Characterize the likely airborne concentrations Characterize the likely airborne concentrations of benzene associated with the handling or use of benzene associated with the handling or use of products containing low levels of benzeneof products containing low levels of benzeneGenerate a robust data set for evaluating Generate a robust data set for evaluating historical occupational exposures to benzenehistorical occupational exposures to benzene
Key Information SourcesKey Information SourcesPeerPeer--reviewed literaturereviewed literatureRegulatory agencies and Regulatory agencies and scientific bodies scientific bodies NIOSH health hazard NIOSH health hazard evaluations (evaluations (HHEsHHEs))Manufacturer Manufacturer MSDSsMSDSsData submitted to OSHA Data submitted to OSHA during benzene rulemakingduring benzene rulemaking
Solvent suppliersSolvent suppliersTrade associationsTrade associationsIndependent research Independent research contractorscontractors
Historical Benzene Content of Historical Benzene Content of PetroleumPetroleum--Derived ProductsDerived Products
The benzene content of various commercial products The benzene content of various commercial products in the U.S. has decreased significantly over last 30 yearsin the U.S. has decreased significantly over last 30 years
Changes in refining practicesChanges in refining practicesRegulatory requirements (product labeling and workplace Regulatory requirements (product labeling and workplace monitoring)monitoring)
However, benzene may still be present as an impurity However, benzene may still be present as an impurity or residual component of mixed petroleum productsor residual component of mixed petroleum productsThese concentrations of benzene are typically These concentrations of benzene are typically considered to be considered to be ““tracetrace”” (i.e., <0.1%) and are not (i.e., <0.1%) and are not thought to pose a risk to public healththought to pose a risk to public health
Reported Benzene Content of Products Reported Benzene Content of Products During the 1950s and 1960sDuring the 1950s and 1960s
AAReportedReported as as w/ww/wBBShellShell discontinued its sale of hexane that contained 3.5% benzene by 1discontinued its sale of hexane that contained 3.5% benzene by 1978978
Review of Published Benzene Air Review of Published Benzene Air Monitoring DataMonitoring Data
Identified 23 studies that evaluated workersIdentified 23 studies that evaluated workers’’exposures to benzene from potential lowexposures to benzene from potential low--level level benzenebenzene--containing products in the U.S. containing products in the U.S. These studies were conducted primarily during These studies were conducted primarily during the 1980s and 1990s, and collectively included the 1980s and 1990s, and collectively included ~1,000 IH measurements for benzene~1,000 IH measurements for benzeneMost studies represented data collected in actual Most studies represented data collected in actual occupational settings during normal workplace occupational settings during normal workplace activities (several were based on simulation activities (several were based on simulation studies)studies)
Types of Products EvaluatedTypes of Products Evaluated
Paints and paint solventsPaints and paint solventsPrinting solvents and inksPrinting solvents and inksDrywall adhesivesDrywall adhesivesHoning and cutting oilsHoning and cutting oilsMineral spirits and degreasersMineral spirits and degreasersJet fuelJet fuel
Paints and Paint SolventsPaints and Paint SolventsFive studies of painters conducted Five studies of painters conducted during the 1980s and 1990sduring the 1980s and 1990s
2 NIOSH 2 NIOSH HHEsHHEs2 peer2 peer--reviewed papersreviewed papers1 DOE report1 DOE report
Workplaces included bus Workplaces included bus maintenance shop, iron foundry maintenance shop, iron foundry casting cleaning facility, casting cleaning facility, construction sites, automotive construction sites, automotive assembly plants, and military bases assembly plants, and military bases Mean airborne concentrations of Mean airborne concentrations of benzene ranged from 0.008 to 0.1 benzene ranged from 0.008 to 0.1 ppm for four studiesppm for four studies
Average concentration of 0.34 ppm Average concentration of 0.34 ppm reported for one study where LOD reported for one study where LOD of 0.1 ppm assigned to nonof 0.1 ppm assigned to non--detect detect samples from the 1980samples from the 1980’’s.s.
Printing Solvents and InksPrinting Solvents and InksEight studies of print shopsEight studies of print shops
Facilities included sheetFacilities included sheet--fed, silk fed, silk screening, and rotogravure printingscreening, and rotogravure printingMean airborne concentrations of Mean airborne concentrations of benzene typically ranged from benzene typically ranged from 0.0001 to 0.5 ppm 0.0001 to 0.5 ppm Higher concentrations (1Higher concentrations (1--2 ppm) 2 ppm) were reported when the benzene were reported when the benzene content of the solvent may have content of the solvent may have exceeded >1% exceeded >1%
Drywall AdhesivesDrywall AdhesivesOne NIOSH HHE One NIOSH HHE conducted in the late conducted in the late 1990s1990sStudy was intended to Study was intended to evaluate solvent vapor evaluate solvent vapor from adhesive during the from adhesive during the hanging of drywall sheets hanging of drywall sheets Airborne concentrations Airborne concentrations of benzene ranged from of benzene ranged from <0.003 to 0.02 ppm<0.003 to 0.02 ppm
Honing and Cutting OilsHoning and Cutting OilsOne NIOSH HHE One NIOSH HHE conducted in the early conducted in the early 1980s1980sStudy was conducted at a Study was conducted at a hydraulics manufacturing hydraulics manufacturing facility that made hydraulic facility that made hydraulic cylinders and used honing cylinders and used honing oils and solvents oils and solvents Airborne concentrations of Airborne concentrations of benzene ranged from benzene ranged from <0.013 to 0.022 ppm<0.013 to 0.022 ppm
Mineral Spirits and DegreasersMineral Spirits and DegreasersThree recent studies involving Three recent studies involving mineral spirits as a cleaning mineral spirits as a cleaning solvent or degreasersolvent or degreaser
Workplace activities included Workplace activities included the spray cleaning of a the spray cleaning of a locomotive generator and locomotive generator and traction motor and mechanical traction motor and mechanical or manual parts washing or manual parts washing Airborne concentrations of Airborne concentrations of benzene ranged from <0.006 to benzene ranged from <0.006 to 0.13 ppm for two studies0.13 ppm for two studies
Maximum concentrations of 0.44 Maximum concentrations of 0.44 to 0.55 ppm in one study to 0.55 ppm in one study involving spiked mineral spirits involving spiked mineral spirits under under ““worst caseworst case”” conditions conditions
Jet FuelJet FuelSix studies of jet fuel exposures in Six studies of jet fuel exposures in 1981 and from late 1990s to 2000s1981 and from late 1990s to 2000s
Operations included aircraft Operations included aircraft maintenance, jet engine repair, fuel maintenance, jet engine repair, fuel handling, and handling, and flightlineflightline tasks tasks Included commercial Jet Fuel A Included commercial Jet Fuel A and military fuels JPand military fuels JP--4, JP4, JP--5, and 5, and JPJP--8 8 Mean airborne concentrations of Mean airborne concentrations of benzene ranged from 0.001 to 0.08 benzene ranged from 0.001 to 0.08 ppmppm
Maximum concentration of 3 ppm Maximum concentration of 3 ppm was reported inside the fuel tankswas reported inside the fuel tanks
Summary of Published Benzene Air Summary of Published Benzene Air Monitoring DataMonitoring Data
Average airborne concentrations of benzene were Average airborne concentrations of benzene were found to typically range from <0.01 to 0.3 ppm for found to typically range from <0.01 to 0.3 ppm for various products based on personal and area shortvarious products based on personal and area short--term term and longerand longer--term samples term samples These findings suggest that occupational exposures to These findings suggest that occupational exposures to benzene during the handling or use of such products benzene during the handling or use of such products were well below historical and current were well below historical and current OELsOELs
ACGIH TLV = 0.5 ppmACGIH TLV = 0.5 ppmOSHA PEL = 1 ppmOSHA PEL = 1 ppm
Higher air concentrations (1Higher air concentrations (1--3 ppm) were occasionally 3 ppm) were occasionally reported, particularly when the reported, particularly when the benzene content of the benzene content of the product may have exceeded 1%product may have exceeded 1%
18 of 23 studies 18 of 23 studies –– 95% confidence that exposures were 95% confidence that exposures were below the TLV 95% of the timebelow the TLV 95% of the time19 of 23 studies 19 of 23 studies –– 95% confidence that exposures were 95% confidence that exposures were below the PEL 95% of the timebelow the PEL 95% of the timeIn each case, except one, where the 95In each case, except one, where the 95thth UCL of the EF UCL of the EF exceeded the OEL more than 5% of the time, the exceeded the OEL more than 5% of the time, the benzene concentration in the liquid solvent was not benzene concentration in the liquid solvent was not reported.reported.
based on the study investigatorsbased on the study investigators’’ recommendations the recommendations the benzene contents likely exceeded 0.1%.benzene contents likely exceeded 0.1%.
Indoor Exposure ModelingIndoor Exposure ModelingEstimated 8Estimated 8--hr TWA benzene hr TWA benzene concentrations for three hypothetical concentrations for three hypothetical partsparts--cleaning scenarios using mineral cleaning scenarios using mineral spiritsspirits
Mechanical parts washingMechanical parts washingManual parts washingManual parts washingSpray applicationSpray application
Modeled estimates were intended to Modeled estimates were intended to represent typical exposures over an 8 represent typical exposures over an 8 hour workday, rather than potential hour workday, rather than potential shortshort--term peak exposuresterm peak exposures
Monte Carlo analysis was performed Monte Carlo analysis was performed tto account for potential variability or o account for potential variability or uncertainty in model input parameters uncertainty in model input parameters
Near Field Near Field VolumeVolume
Far Field Volume
Air flow intowarehouse
Air flow out ofwarehouseNear Field
Airflow
TwoTwo--Zone ModelZone ModelBenzene air concentrations were estimated in the breathing zone Benzene air concentrations were estimated in the breathing zone (near field) and general workplace air (far field)(near field) and general workplace air (far field)Assumed that mineral spirits was used for 8 hours in a Assumed that mineral spirits was used for 8 hours in a warehouse with no mechanical or local exhaust ventilationwarehouse with no mechanical or local exhaust ventilationInput data for building parameters and benzene content were Input data for building parameters and benzene content were based on based on NicasNicas et al. (2006) and et al. (2006) and FedorukFedoruk et al. (2003)et al. (2003)
Modeled Airborne Concentrations of Modeled Airborne Concentrations of Benzene Over 8 Hour WorkdayBenzene Over 8 Hour Workday
NearNear--field 8field 8--hour TWA benzene hour TWA benzene concentrations were 0.2 ppm (50concentrations were 0.2 ppm (50thth
percentile) and 0.4 ppm (95percentile) and 0.4 ppm (95thth
percentile) for mechanical partspercentile) for mechanical parts--washing (Solid Black line)washing (Solid Black line)For manual partsFor manual parts--washing, washing, modeled nearmodeled near--field concentrations field concentrations were 1/20 to 1/1000 those of were 1/20 to 1/1000 those of mechanical partsmechanical parts--washing (Middle washing (Middle dashed line)dashed line)Application of a timeApplication of a time--activity activity pattern would more accurately pattern would more accurately reflect historical exposures to reflect historical exposures to benzene during typical degreasing benzene during typical degreasing operationsoperations
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
0.00001 0.001 0.1 10Benzene Air Concentration (ppm)
Perc
entil
e
(A) Near Field (breathing zone)
Incorporating TimeIncorporating Time--Activity Pattern Activity Pattern During Mechanical Parts WashingDuring Mechanical Parts WashingSolvents in parts washers Solvents in parts washers are typically replaced are typically replaced with fresh solvent on a with fresh solvent on a two or 4 week cycle.two or 4 week cycle.Benzene concentration Benzene concentration in liquid solvent will be in liquid solvent will be depleted over time.depleted over time.Modeled near field 8Modeled near field 8--hr hr TWA concentrations TWA concentrations assuming daily operation assuming daily operation duration of 2 hours/dayduration of 2 hours/day
88--hr TWA Benzene hr TWA Benzene Concentration (ppm)Concentration (ppm)
0.030.030.010.0144--weekweek
0.060.060.030.0322--weekweek
88--hr TWA hr TWA (ppm)(ppm)9595thth
PercentilePercentile
88--hr TWA hr TWA (ppm)(ppm)5050thth
PercentilePercentile
Replacement Replacement CycleCycle
ConclusionsConclusions
PetroleumPetroleum--derived products containing <0.1% benzene derived products containing <0.1% benzene are not expected to produce 8are not expected to produce 8--hour TWA airborne hour TWA airborne concentrations that exceed current regulatory standards concentrations that exceed current regulatory standards under typical product use scenariosunder typical product use scenariosOSHA reached the same conclusion in the late 1980s, OSHA reached the same conclusion in the late 1980s, which is why product which is why product MSDSsMSDSs are only required to list are only required to list benzene if it is present at >0.1% unless 8benzene if it is present at >0.1% unless 8--hour TWA hour TWA exposures are expected to exceed occupational health exposures are expected to exceed occupational health standards under specific conditions standards under specific conditions
