Occupational Cancer
Tim Morse, Ph.D.Tim Morse, Ph.D.University of Connecticut Health University of Connecticut Health
Center, Farmington, CT, USCenter, Farmington, CT, US
Spring 2000Spring 2000
Objectives Theoretic concerns in identifying carcinogens Estimates of occupational cancer Known exposures and occupations related to
occupational cancer Asbestos and cancer: case study
History Risks Control U.S. Regulations
Issues
Multiple causation & interaction Multiple stages Latency period Threshold level
Testing for Cancer
Analysis of structure-activity relations Cell tests Animal studies Epidemiologic studies
Problems in testing
Prolonged high exposure is uncommon Usually mix of exposures Epi: expensive, long, past exposures,
poor exposure data Animal: high dose, ? Validity in humans In vitro: mutagens, not carcinogens
How much cancer is occupational?
Doll & Peto (1981) 2-8% Viewed as conservative For US, 25,000-100,000 new cases/year Higher proportions for exposed
workers
NJ Cancer Registry by Industry Excess:
Nasopharyngeal: carpenters and other blue collar special trade construction
Colorectal: machinery manufacturing, printing Liver: general construction and rubber and plastics Gallbladder: electrical equipment Lung: primary metals, shipbuilding, construction, and
stone, clay, and glass Mesothelioma: shipbuilding and asbestos manufacturing
NJ Cancer Registry by Industry Excess: Breast: (Black females) chemical and
pharmaceutical Bladder: (white males) apparel and textile
industries. Non-Hodgkin's lymphoma:
(white females) printing (white male) bakers and motor vehicle manufacturing
Lymphocytic leukemia: chemical and construction
Lung cancer (Steenland, 1996)
silica asbestos diesel engine
exhaust radon progeny arsenic
chromium, beryllium, nickel, and cadmium acrylonitrile
Lung Cancer Annual Incidence (Steenland, 1996)
9,000-10,000 men 900-1,900 women half asbestos
Non-Hodgkins Lymphoma (Figgs, 1995) 24 state death certificate study: 47
occupations, and 28 industries. firefighters, farm managers, aircraft mechanics, electronic repairers, mining machine operators, and crane and tower operators also white collar
Women
25% increase in lung cancer among production workers (9% decrease overall cancer) (Delzell, 1994)
Breast cancer tissue had 50-60% higher levels of DDT and PCB’s (Wolff, 1993)
38% Breast cancer increase in electrical workers (217% for telephone installers) (Loomis, 1994)
Review of breast cancer (Goldberg, 1996)
Limited evidence: pharmaceutical industry and among cosmetologists and beauticians
Possible associations: chemists and occupations with potential exposure to extremely low frequency electromagnetic fields.
Little support: textiles workers, dry cleaning workers, and nuclear industry workers
Roofers & asphalt workers (meta analysis: Partanan, 1994)
Stomach cancer bladder cancer skin cancer leukemia
Firefighters review (Golden, 1995) leukemia, nonHodgkin's lymphoma, multiple myeloma, cancers of the brain, urinary bladder,
and possibly from cancer of the prostate,
large intestine, and skin.
Construction workers review (Sullivan, 1995):
Lung (70% increase from NHIS, 1988), larynx, oropharyngeal and nasal cancers, mesothelioma,
Dry cleaning using perchloroethane (Ruder, 1994)
23% increase among 20-year workers
esophogeal, intestinal, bladder
Cutting fluid exposure (Eisen, 1992)
85% increase of laryngeal cancer (also stomach)
Occupational Cancer
IARC: ID carcinogens by worker studies 21/22 lung carcinogens 34/62 carcinogens overall
Asbestos and Health
Overview
Background on asbestos Uses of asbestos Health Effects Risk factors Medical tests Proper handling Standards/ guidelines
What is Asbestos?
Mineral Fibrous White/grey Indestructible Fireproof
How Long Has it Been a Problem?
Early Greek miners wore face masks from animal bladders
Insurers stopped selling insurance in 1915 Cancer cases in 1930’s Asbestos industry withheld information Selikoff studies in 1960’s Banning of some uses in 1980’s
Uses of Asbestos
Fireproofing of buildings Heat insulation Strengthen building materials
Products that can contain asbestos Spray insulation Pipecovering Asbestos cloth Cements, mastic, sealants Roofing materials Floor & ceiling tiles Plaster & taping compound
Hazards of Asbestos
Harmful only when breathed in (maybe when swallowed)
Fiber shape: long, thin Travels in air, gets deep in lungs Sharp shape gets stuck in lungs Doesn’t break down
Asbestos Diseases
Asbestosis Pleural Plaques Cancer
Lung Mesothelioma G-I Tract
Asbestos Diseases
No completely safe levels Higher the exposure, higher the risk Low exposures have low risk Everyone exposed to asbestos Lag time (latency) of 10-40 years No acute effects
Asbestosis
Not cancer Scarring of lungs From high exposures Causes shortness of breath
Pleural Plaques
Scars on lungs Shows up on x-rays Marker of asbestos exposure Half of heavily exposed will have “Not a disease”: no symptoms Does not change into cancer Legally considered a disease
Lung cancer
Most common problem with asbestos Heavily exposed workers have 5-7 times
increased risk over lifetime About same level of risk as a pack a day
cigarette smoking Interacts with cigarettes: 50-90 times
increased risk for both combined Quitting smoking reduces risk
Other Cancers
Mesothelioma Cancer of lining of the lungs Only caused by asbestos Smoking not a risk factor
G-I tract cancer 2-3 times increased risk for heavily
exposed
Medical tests
Physical History X-rays Lung function tests
What is Risk?
Studies are from heavily exposed asbestos workers
Construction trades working with asbestos have 1/4 or less risk than asbestos workers
Chemical plant maintenance has about 1/8 Other maintenance workers are much lower Asbestos has been phased out & removed in
many areas
Safe handling of asbestos
Find out where the asbestos is Management plan Remove if needed by licensed contractors Only dangerous if is in the air
Removal may be more dangerous than leaving If is bound in material (tiles, etc) is not a hazard
Should be labeled if left in place
“Safe” handling of asbestos
No absolutely safe exposure Wet methods HEPA vacuums and respirators Never dry sweep or compressed air Stays in air for days Small fibers can’t be seen “Friable” asbestos means it can be crumbled
Maintenance & asbestos
Do not drill, sand, or saw asbestos materials Wet mop rather than dry sweep or dust Do not use a regular vacuum: only HEPA Do not disturb asbestos materials If use a face mask, only HEPA If are air filters, use wet methods, do not
shake
Training/ removal
Removal by certified contractors Enclosures, ventilation, wet methods, HEPA Glove bags, wetting agents, signs
Encapsulation Training needed based on level of exposure Level 4 for clean up of asbestos containing
materials Proper disposal while still wet; labeled bags
Regulations
EPA regulations on removal OSHA Standard for general industry or
construction State licensing for asbestos removal Workers’ compensation Reporting of suspected occupational
diseases
EPA:Control of Asbestos in Buildings
Survey to see if asbestos is present Operations and Management Program Assess the asbestos Abatement if needed
Survey
Appoint manager & team Check building records Locate & document all asbestos in
records Inspect for friable Collect & test samples Document
Operations and Maintenance Contact building managers & maintainers Educate employees and occupants Train custodians/ maintainers Clean using HEPA & wet methods; regular
basis Special precautions for construction work Inspect twice a year Continue program until all asbestos removed
Assess Asbestos
Assess current conditions and chances of disturbance
Determine Need for further action When it needs to be done What abatement methods to use
Conduct Abatement if Needed
Hire contractor: To select:
Precise contractCheck referencesInterviewInsuranceBest, not low bid
Managing Abatement Inspect 4 times a day
Containment barrier Coveralls & respirators Changing & decontamination facilities
Stop work if problem Release only when
Cleaned at least twice Visual test Airborne asbestos test
OSHA Standard Applies if over maximum exposure Maximum of 0.2 fibers per cc of air (8
hour) Maximum of 1 fiber per cc (30 minute) Exposure monitoring if above action
level (0.1 fiber per cc) Engineering controls where feasible Proper respirators
OSHA Standard (2)
Regulated areas Labels Recordkeeping for 30 years Protective clothing Change rooms & showers Medical Exams
Top Related