1. Occupational Cancer Tim Morse, Ph.D. University of Connecticut Health Center, Farmington, CT, US Spring 2000

2. 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

3. Issues • Multiple causation & interaction • Multiple stages • Latency period • Threshold level

4. Testing for Cancer • Analysis of structure-activity relations • Cell tests • Animal studies • Epidemiologic studies

5. 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

6. 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

7. 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

8. 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

9. silica asbestos diesel engine exhaust radon progeny arsenic chromium, beryllium, nickel, and cadmium acrylonitrile Lung cancer (Steenland, 1996)

10. Lung Cancer Annual Incidence (Steenland, 1996) • 9,000-10,000 men • 900-1,900 women • half asbestos

11. 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

12. 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)

13. 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

14. Roofers & asphalt workers (meta analysis: Partanan, 1994) • Stomach cancer • bladder cancer • skin cancer • leukemia

15. 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.

16. Construction workers review (Sullivan, 1995): • Lung (70% increase from NHIS, 1988), • larynx, • oropharyngeal and nasal cancers, • mesothelioma,

17. Dry cleaning using perchloroethane (Ruder, 1994) • 23% increase among 20-year workers • esophogeal, intestinal, bladder

18. Cutting fluid exposure (Eisen, 1992) • 85% increase of laryngeal cancer (also stomach)

19. Occupational Cancer • IARC: ID carcinogens by worker studies • 21/22 lung carcinogens • 34/62 carcinogens overall

20. Asbestos and Health

21. Overview • Background on asbestos • Uses of asbestos • Health Effects • Risk factors • Medical tests • Proper handling • Standards/ guidelines

22. What is Asbestos? • Mineral • Fibrous • White/grey • Indestructible • Fireproof

23. 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

24. Uses of Asbestos • Fireproofing of buildings • Heat insulation • Strengthen building materials

25. Products that can contain asbestos • Spray insulation • Pipecovering • Asbestos cloth • Cements, mastic, sealants • Roofing materials • Floor & ceiling tiles • Plaster & taping compound

26. 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

27. Asbestos Diseases • Asbestosis • Pleural Plaques • Cancer • Lung • Mesothelioma • G-I Tract

28. 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

29. Asbestosis • Not cancer • Scarring of lungs • From high exposures • Causes shortness of breath

30. 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

31. 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

32. 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

33. Medical tests • Physical • History • X-rays • Lung function tests

34. 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

35. 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

36. “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

37. 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

38. 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

39. Regulations • EPA regulations on removal • OSHA Standard for general industry or construction • State licensing for asbestos removal • Workers’ compensation • Reporting of suspected occupational diseases

40. EPA:Control of Asbestos in Buildings • Survey to see if asbestos is present • Operations and Management Program • Assess the asbestos • Abatement if needed

41. Survey • Appoint manager & team • Check building records • Locate & document all asbestos in records • Inspect for friable • Collect & test samples • Document

42. 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

43. 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

44. Conduct Abatement if Needed • Hire contractor: • To select: • Precise contract • Check references • Interview • Insurance • Best, not low bid

45. 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

46. 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

47. OSHA Standard (2) • Regulated areas • Labels • Recordkeeping for 30 years • Protective clothing • Change rooms & showers • Medical Exams