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