8281 by pengtt


									Occupational Cancer

      Tim Morse, Ph.D.
 University of Connecticut Health
  Center, Farmington, CT, US
           Spring 2000
 Theoretic concerns in identifying
 Estimates of occupational cancer
 Known exposures and occupations
  related to occupational cancer
 Asbestos and cancer: case study
     History
     Risks
     Control
     U.S.   Regulations
 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
 Usually mix of exposures
 Epi: expensive, long, past exposures,
  poor exposure data
 Animal: high dose, ? Validity in
 In vitro: mutagens, not carcinogens
How much cancer is

 Doll   & Peto (1981) 2-8%
  Viewed as conservative
  For US, 25,000-100,000 new cases/year
  Higher proportions for exposed
      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
   Gallbladder: electrical equipment
   Lung: primary metals, shipbuilding,
    construction, and stone, clay, and glass
   Mesothelioma: shipbuilding and asbestos
NJ Cancer Registry by
Industry Excess:
 Breast: (Black females) chemical and
 Bladder: (white males) apparel and
  textile industries.
 Non-Hodgkin's lymphoma:
     (white females) printing
     (white male) bakers and motor vehicle
   Lymphocytic leukemia: chemical and
Lung cancer (Steenland, 1996)
 silica           chromium,
 asbestos         beryllium,
 diesel engine    nickel, and
  exhaust          cadmium
 radon progeny
                   acrylonitrile
 arsenic
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
 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
 Possible associations: chemists and
  occupations with potential exposure to
  extremely low frequency electromagnetic
 Little support: textiles workers, dry
  cleaning workers, and nuclear industry
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,
 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
 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
 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
 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
 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
  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

 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
  2-3times increased risk for heavily
Medical tests
 Physical
 History
 X-rays
 Lung   function tests
    What is Risk?
 Studies are from heavily exposed asbestos
 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
 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
   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
Maintenance & asbestos
 Do not drill, sand, or saw asbestos
 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
    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
 Proper disposal while still wet; labeled
 EPA regulations on removal
 OSHA Standard for general industry or
 State licensing for asbestos removal
 Workers’ compensation
 Reporting of suspected occupational
Control of Asbestos in Buildings
 Survey to see if asbestos is present
 Operations and Management Program
 Assess the asbestos
 Abatement if needed
 Appoint manager & team
 Check building records
 Locate & document all asbestos in
 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
Assess Asbestos
 Assesscurrent conditions and
  chances of disturbance
 Determine
  Needfor further action
  When it needs to be done
  What abatement methods to use
Conduct Abatement if Needed
 Hire   contractor:
  To    select:
    Precise contract
    Check references



    Best, 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
  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

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