Asbestosboritcag.org/pdf/Asbestos - by Hila Wright UCLA 2005 an overview.pdf · (Chrysotile) • It...

Instructor Dr. Eckhert EHS201 UCLA 2005

ASBESTOS

By Hila Wright



Presentation Outline

• Background information: Why is asbestos significant?

• Chemical/Physical characteristics and toxicology• Risk factors for asbestos exposure and asbestos-

related disease• Elimination methods and replacement products• Regulations


BACKGROUND--Why is asbestos interesting?

• It is a known carcinogen• It was widely used in the US in various

products, such as building materials • Still currently in use in some products in US

(roofing, gaskets, friction parts)• Ongoing asbestos abatement in buildings• Current litigation issue• The California State rock (serpentine)


Fate & Transport

• TERRESTIRAL FATE: Movement of asbestos fibers only occur during runoff or erosion. Asbestos fibers will not volatilize or degrade although they may be re-suspended to the air by vehicular traffic over unpaved soil surfaces containing asbestos or through mining and milling operations


Fate & Transport continued. . .

• AQUATIC FATE: Asbestos will not degrade in water.

• ATMOSPHERIC FATE: Asbestos released to the air will eventually settle out by gravitational settling and dry deposition. In US cities, average concentration of 2-4 ng/cu m


Historical Significance

• Due to some of its physical and chemical properties, asbestos has been mined, milled, and used in thousands of products in the US and abroad

• Egyptian burial cloths & Charlemaigne’stable cloth

• US Regulations starting in 1970’s


Some Asbestos-Containing Products


Where Can Asbestos be Found?• Cement Pipes

• Laboratory Hoods/Table Tops

• Elevator Brake Shoes

• Cement Wallboard

• Laboratory Gloves

• HVAC Duct Insulation

• Cement Siding

• Fire Blankets

• Boiler Insulation

• Asphalt

• Floor Tile

• Construction Mastics (floor

• tile, carpet, ceiling tile, etc.)

• Wallboard Heating and Electrical

• Ducts

• Acoustical Plaster Joint Compounds

• Vinyl Wall Coverings

• Decorative Plaster Spackling Compounds

• High Temperature Gaskets

• Textured Paints/Coatings

• Roofing Shingles Roofing Felt

• Ceiling Tiles


Where Can Asbestos be Found? Continued. . .

• Pipe Insulation (corrugated air-cell, block, etc.)

• Fire Curtains

• Vinyl Floor Tile

• Elevator Equipment Panels

• Flexible Fabric

• Vinyl Sheet Flooring

• Caulking/Putties

• Cooling Towers

• Flooring Backing Adhesives

• Pipe Insulation

Thermal Paper Products

Spray-Applied Insulation

Fire Doors

Electrical Cloth

Blown-in Insulation

Electrical Panel Partitions

Fireproofing Materials

Taping Compounds

Electric Wiring Insulation

Chalkboards







Adverse Health Effects

• Asbestosis (fibrous scarring of the lung)• Lung cancer• Mesothelioma (Very rare, and primarily

associated with asbestos exposure)• Gastrointestinal cancer• Significant elevation in the incidence of

cancers of the larynx, pharynx and buccalcavity, and kidney


Description of Contaminant & its Toxicology


Physical & Chemical Characteristics

• Forms long thin fibers• Tensile strength (matrix

re-enforcement)• Thermal & electrical

insulation• Sound insulation• Non-flammable• Adsorption capacity• Wear & friction properties


Asbestos Chemical Structure

• Asbestos is a mineral composed primarily of silica, magnesium and water.

• Asbestos is classified as serpentines and amphiboles.


Types of Asbestos

• Serpentine (Chrysotile)

• It has a layered structure made up of SiO4 tetrahedral and Mg(OH)2 layers.

• The mismatch between those two types of layers is responsible for a curvature in the structure cylindrical/tubular form of the chrysotile fibres.

• The connections between the layers are weak, giving the chrysotile asbestos fibres a great flexibility

• Amphiboles• The amphibole structure is formed by

double Si and O chains. • The chains are connected by other

elements like Na, Mg, Ca en Fe.• Amphibole fibres have a diamond-shaped

cross-section. • They are less flexible than serpentine

fibres, and they tend to split into small, very sharp splinters.



Asbestos Types

• Serpentine • Amphyboles


Species Variety Chemical composition

chrysotile serpentine 3MgO.2SiO2.2H2O

anthophyllite amphibole 7MgO.8SiO2.H2O

amosite amphibole 11FeO.3MgO.16SiO2.2H2O

actinolite amphibole 2CaO.4MgO.FeO.8SiO2.H2O

tremolite amphibole 2CaO.5MgO.8SiO2.H2O

crocidolite amphibole Na2O.Fe2O3.3FeO.8SiO2.H2O


Chemical/Physical Characteristics & its Uses

• Serpentine (Chrysotile)– Comprises majority of

asbestos used commercially

– Can be woven into fabrics

• Amphyboles– Primarily used for

thermal systems insulation (pipe lagging, etc.).


Adverse Health Effects


Toxicology of Asbestos

• Respiratory route is the most important• Gastrointestinal and dermal routes less significant• The majority of inhaled asbestos is either exhaled

or becomes lodged in phlegm and is then excreted through the GI tract.

• Once an asbestos fiber reaches the alveoli, it can become lodged in the lung for years.

• Some asbestos fibers can become dislodged from the alveolar wall, and be transported elsewhere


Toxicology of asbestos continued

• Fibers can accumulate in the lung, and cause inflammation and scarring affects breathing, leading to disease = Asbestosis (10-30 year latency period)

• Lung Cancer (15-20 year latency period)• Mesothelioma of the plura of the lungs or the

peritoneum of the abdomen (20-40 year latency)• Amphiboles remain in lung longer, and may

therefore be more harmful


Pathology of Asbestosis

• Fibers retained in the lung are <3- 200 um• A portion of the fibers become coated with an iron protein

complex • All types of asbestos cause microphage-mediated fibrosis.

The areas increase in size and coalesce causing diffuse fibrosis with shrinkage.

• The process starts in the bases spreading upwards as the disease progresses; in advanced disease the whole lung structure is distorted and replaced by dense fibrosis, cysts, and some areas of emphysema.


Asbestosis Photographs





Toxicology of Asbestos as a Carcinogen

Lung CancerMesothelioma


Asbestos Mutagenicity

• Reactive Oxygen Species (=Inflammation & macrophages). – Size– Shape– Chrystallinity– Solubility– Distance between DNA &

sources of ROS

• Oxide-reduction processes– Iron reactivity– Phagocytosis

• Altered Gene Expression– Cell proliferation


Demonstration of Genotoxicity

• In-vivo chromosomal aberrations• Impaired mitosis

– chromosome missegregation– spindle changes– alteration of cell cycle progression– aneuploid and polyploid cells– nuclear disruption



Asbestos-Related Lung Cancer


Mesothelioma Photographs


Mesothelioma development over time





Risk Factors


“Historical” Target Occupations...

• Asbestos textile mill workers• Automobile workers& repairers• Building material manufacturers• cement plant production workers• construction workers (including

insulators, boilermakers, laborers, steel/ironworkers, plumbers, steam fitters, plasterers, drywallers, cement and masonry workers, roofers, tile/linoleum installers, carpenters, HVAC mechanics and welders)

• Electrical workers, including electricians, electrical linemen, and telephone linemen

• Shipyard workers (including electricians, insulators, laborers, laggers, painters, pipefitters, maintenance workers, and welders)

• Custodians, insulation manufacturing plant workers, insulators, machinists, packing and gasket manufacturing plant workers, pipefitters, and powerhouse workers

• Railroad workers, steamfitters, refinery workers, sheetmetalworkers, refractory products plant workers, rubber workers

• aerospace and missile production workers, aircraft manufacturing production workers, and aircraft mechanics

• Miners


Current Target Occupations

– Asbestos abatement workers– Plumbers– Electricians– Construction workers/demo crews– Miners (not US)– Automobile repairers


Target Populations Continued. . .

• Families of occupationally exposed workers• Persons living near asbestos mines• Persons living in areas with asbestos-rich

soils• Persons occupying building with asbestos-

containing materials (ACM) in poor conditions , or ACM being disturbed

• Persons located near such buildings


Additional Risk Factors

• Exposure concentration - what was the concentration of asbestos fibers?• Exposure duration - how long did the exposure time period last?• Exposure frequency - how often during that time period was the person exposed?• Size, shape and chemical makeup of asbestos fibers


Additional Risk Factors

SMOKING!!• Estimates of 50% to 90x increased cancer

risk (Synergetic)• If a smoker has an asbestos exposure

history, they can reduce their risk of developing an asbestos-related respiratory disease if they stop smoking.


Methods of Elimination from the Environment


Asbestos Abatement1. Not all ACBM must be removed2. The removal of ACBM is regulated and

includes:• Use of PPE• Preparation of work site• Construction of Containment & decontamination chambers• Work to be performed under the supervision of a competent

person• Removal to be performed using wet methods• Debris to be bagged and disposed of appropriately• No visible emissions• Post-cleaning• Personnel Monitoring• Clearance sampling must or should be conducted• Post-removal strike-down, lockdown and application of

substitutes


Personal Protective Equipment• Safety/rubber boots• Disposable protective

clothing• Head covering• Leather gloves• Hard hats• Eye protection • Respirator

– ½ face– Full-face– PAPR– Supplied Air


Preparation of Work-Site

• Personnel records• Sign-in sheets• Lock-out/tag-out• Pre-clean the room• Remove contents from

room and/or cover


Construction of Containment

Containment:1. Cover windows, doors,

HVAC supplies and intakes, floor.

2. Use 6-mil polyvinyl sheeting to construct containment

Decontamination ChambersEstablish AreaPost Signage


Removal to Be Performed Using Wet Methods


Debris to be bagged wet, and disposed of appropriately


Clearance Criteria

• ACM removed as necessary

• No debris/dust• Passing air sample

results:– 0.01 fibers/cc PCM– 70 structures/mm2

TEM


Replacement AgentsProduct Type Uses Replacement Asbestos-containing fabrics/papers

InsulationPipe laggingTheater curtainsThermal systems insulationBeer/wine filters

FiberglassSyntheticKevlarCeramicCellulose products

Asbestos-containing cements/plasters

StuccoConcreteCement pipesCement boards

PerliteCeramic fiberNon-asbestos mineralsMineral woolDiatomacious earth & lime

Asbestos-containing break linings or disks

BreaksClutches

SyntheticsMetallic fiberGlass fiber


Regulations


Federal Regulations

• EPAAsbestos Hazard Emergency Response Act under TSCA (AHERA, 40 CFR 763)Asbestos School Hazard Abatement Reauthorization Act under TSCA (ASHERA) National Emission Standards for Hazardous Air Pollutants under Clean Air Act (NESHAP, 40 CFR 61 part M)Clean Water Act (EPA 7 mf/l [million fibers/l])

• OSHA– Construction Industry (29CFR 1926.1101)– General Industry (29 CFR 1910.1001)– Shipyard Workers (29 CFR 1915.1001)


AHERA• Subpart E--Asbestos-Containing Materials in Schools

– Appendix A to Subpart E--Interim Transmission Electron Microscopy Analytical Methods--Mandatory and Nonmandatory--and Mandatory Section to Determine Completion of Response Actions

– Appendix C--Asbestos Model Accreditation Plan– Appendix D--Transport and Disposal of Asbestos Waste – Appendix E--Interim Method of the Determination of Asbestos In

Bulk Insulation Samples • Subpart G--Asbestos Worker Protection • Subpart I--Prohibition of the Manufacture, Importation, Processing, and

Distribution in Commerce of Certain Asbestos-Containing Products; Labeling Requirements


AHERA Subpart I (TSCA Ban)

• 1989 EPA announced ban and phase-down rule over 7 years to begin 1990.

• Use of asbestos products would have been banned in US, except products w/o substitutes and military use.

• 1991 Louisiana 5th Circuit Court of Appeals vacated regulation. Only 6 product categories subject to Ban & Phase-out rule:


Result of TSCA Appeal Finding

Products still subject to ban:

1. Corrugated paper2. Roll board3. Commercial paper4. Specialty paper5. Floor felt6. New uses

Products not subject to ban:

– asbestos-cement corrugated sheet, asbestos-cement flat sheet, asbestos clothing, pipeline wrap,

– roofing felt, vinyl-asbestos floor tile, asbestos-cement shingle, millboard, asbestos-cement pipe,

– automatic transmission components, clutch facings, friction materials, disc brake pads, drum

– brake linings, brake blocks, gaskets, non-roofing coatings, and roof coatings.


ASHARA

• Model Accreditation Plan• Extends AHERA requirements to public

and commercial buildings


NESHAP

• Protects the public by minimizing the release of asbestos fibers during activities involving the processing, handling, and disposal of ACM

• Notification requirements• Work practices standard• Zero visible emissions to outside air• NESHAP Regs apply to removal of 260 LF or 160

SF of Regulated ACM• Locally, NESHAP is enforced by S. Cal. Air

Quality Management District.


NESHAP Product Bans

• Most spray-applied surfacing materials containing >1% asbestos (unless encapsulated, non-friable & no emissions)

• Fireproofing• Decorative

• Thermal System Insulation• Pipe insulation• Insulation for boilers


OSHA

• Permissible Exposure Limit: 0.1 fibers/cc• 30 min Excursion Limit: 1 fiber/cc


OSHA—General Industry

• Worker Protection– Medical Surveillance– Respiratory protection– Work practices & engineering controls– Personnel exposure monitoring– Smoking cessation

• Bulk sample analysis


OSHA—Shipyard Workers

• Worker Protection– Medical Surveillance– Respiratory protection– Work practices & engineering controls– Personnel exposure monitoring– Smoking cessation

• Bulk sample analysis


OSHA—Construction Industry

• Applies to:– Demolition– Renovation– Maintenance/repair– Emergency clean-up– Transportation/disposal

• Does not apply to asphalt roof coatings, cement and mastics.


OSHA—Construction Industry Continued. . .

• Work area protection• Worker protection• Exposure assessments

– Negative Exposure assessments• Engineering controls• Work practices/housekeeping


State Regulations

• Cal/OSHAConstruction Industry (CCR,Title 8, Section 1529)General Industry (Section 5208 of General Industry Safety Orders).

• Cal/EPADepartment of Toxic Substance Control


Fed OSHA vs. Cal OSHA

• Fed OSHA regulations apply if material contains >1% asbestos

• Cal OSHA regulations apply if material contains >0.1% asbestos


Local Regulations

local fire department County and city Ordinance


Summary

• Asbestos has been widely used• It is a known carcinogen and lung disease

hazard, with latency periods 10-40 yrs.• Numerous occupations historically & presently

at risk for exposure.• Currently it is heavily regulated

How important is it really in EHS?


References• http://www.epa.gov/asbestos/• http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=9995• http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=10862• http://www.osha.gov/SLTC/asbestos/• http://www.osha.gov/SLTC/constructionasbestos/• http://www.atsdr.cdc.gov/asbestos/• http://toxnet.nlm.nih.gov/cgi-bin/sis/search/f?./temp/~6EIoyw:1• http://toxnet.nlm.nih.gov/cgi-bin/sis/search/f?./temp/~5JKyOO:1• http://toxnet.nlm.nih.gov/cgi-bin/sis/search/f?./temp/~s0N5o1:1• Roach, H. D, et al, “Asbestos: When the Dust Settles—An Imaging Review of Asbestos-related

Disease,” Radiographics 2002;22:S167-S184.• Schins, R. D, “Mechanisms of Genotoxicity of Particles and Fibers,” Inhalation Toxicology 2002;

14(1):57-78• Jaurand, M. C, “Mechanisms of Fiber-Induced Genotoxicity,” Environmental Health Perspectives

1997;105:S5:1073-1084• Barrett, J. C, Shelby, M. D, “Mechanisms of Human Carcinogens,” Progress in Clinical and

Biological Research 1992; 374:415-434.• McCrone, W. C, Asbestos Identification, G&G Printers, 1988• NATEC Inernational, Inc., Asbestos Contractor Supervisor Refresher Course.• California Code of Regulations, Title 8, Section 1529• California Code of Regulations, Title 8, Section 5208

http://www.epa.gov/asbestos/

http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=9995

http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=10862

http://www.osha.gov/SLTC/asbestos/

http://www.osha.gov/SLTC/constructionasbestos/

http://www.atsdr.cdc.gov/asbestos/

http://toxnet.nlm.nih.gov/cgi-bin/sis/search/f?./temp/~6EIoyw:1

http://toxnet.nlm.nih.gov/cgi-bin/sis/search/f?./temp/~5JKyOO:1

http://toxnet.nlm.nih.gov/cgi-bin/sis/search/f?./temp/~s0N5o1:1


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