Occupational Health and Safety: An Overview

Emory University - Rollins School of Public Health
Atlanta, Georgia

Instructor(s): Frumkin, Howard
Subject area: Health / Medicine
Department: Public Health
Level: Undergraduate Medical
Number of participants: 90
Duration of exercise: 90 minutes
Cost/equipment needed: None
Learning objective: Provide Information
Teaching style: Passive Learning

Please note that the copyright for this course project is retained by the instructor.



This lecture is presented to first year medical students at Emory University as part of their Patient/Doctor Course. This lecture provides a broad overview of the field of occupational health and safety. The lecture begins with a discussion of what the field is and why it is relevant, citing the extent of occupational illnesses and injuries in the United States each year. The most common work-related diseases and injuries are then reviewed, followed by some guidelines on taking an occupational history. Next, the resources that are available to help provide additional information are then discussed. The lecture concludes with a brief discussion of preventive strategies, the legal and administrative arrangements, and current issues in occupational health and safety.


The Patient/Doctor Course
March 20, 1996


I. INTRODUCTION

A. Some scenarios you might encounter

1. A pregnant woman who works as a laboratory technician asks her obstetrician if she should change her job or stop working because of the chemicals to which she and her fetus are exposed.

2. A middle-aged man sees an orthopedic surgeon and states that he is totally disabled from chronic back pain, which he attributes to many years of lifting heavy objects as a warehouse worker.

3. A long-distance truck driver asks his cardiologist how soon after his recent myocardial infarction he will be able to return to work and what kinds of tasks he will be able to perform.

4. A former asbestos worker with lung cancer asks his surgeon if he can submit a claim for workers' compensation for his disease.

5. An oncologist observes an unusual cluster of bladder cancer cases among middle-aged women in a small town.

6. The vice-president of a small tool and die company asks his local family physician to advise his company regarding prevention of occupational disease among his employees.

7. A pediatrician diagnoses lead poisoning in a young child and wonders if the source of the lead may be the dust brought home on the workclothes of the father, who works in a battery plant.

8. Three women who work for a plastics company, all complaining of headaches and severe rashes on their hands and arms, consult an internist, who believes their problems may be work-related.

B. Definitions

1. Overall definition of the field.

2. Safety vs. health.

3. OHS is a clinical field, emphasizing diagnosis, treatment, and prevention, and also a public health field, emphasizing research and prevention.

4. In OHS medicine intersects many other disciplines and concerns:
a. industrial hygiene
b. epidemiology
c. labor law
d. personnel management
e. nursing

C. Occupational medicine

1. A specialty with its own residency training and Board certification.

2. Occupational medicine specialists work in academic centers, industry, managed care and HMO settings, consulting firms, and government agencies.

D. The extent of the problem

1. Injuries: 5-20 million per year in the U.S., of which 5,000-10,000 are fatal.

Incidence of Workplace Injuries per 100 Full-Time Employees by Industry, 1993
IndustryIncidence
Agriculture, forestry, fishing10.6
Mining6.5
Construction12.0
Manufacturing10.4
Transportation, utilities9.1
Wholesale and retail trade7.9
Finance, insurance, real estate2.5
Services6.4
Within manufacturing, great variability:
Meat packing plants
Iron and steel foundries
Motor vehicles and equipment
Chemicals and allied products
Women's clothing
Computer and office equipment
.
24.4
22.5
17.7
5.2
4.4
2.6

.
2. Illnesses: 400,000 new occupational illnesses per year, of which 50,000-100,000 are fatal.

3. Disability: Almost 2 million persons partially or totally disabled at any given time due to occupational injury or illness.

D. Variation from country to country and within countries, based on levels of technology and prevailing industries.


II. LEADING WORK-RELATED DISEASES AND INJURIES

A. Occupational lung diseases

1. Asbestosis
a. Asbestos: a naturally occurring Mg silicate
b. Population at risk: 7-13 million
c. Selikoff: 10-20% of shipyard and asbestos workers will die of asbestos-related diseases
d. Effects:
1) pleural thickening
2) pulmonary fibrosis
3) lung cancer
4) mesothelioma
e. Synergy with cigarettes

2. Silicosis
a. Ancient disease: Hippocrates wrote of respiratory illnesses of masons, stonecutters, quarrymen
b. Silica is silicon dioxide; free crystalline silica causes silicosis
c. Silicotic nodules, PMF, superimposed infection, especially TB, atypical mycobacteria
d. 60K currently exposed workers will contract some degree of silicosis

3. CWP (Coal Worker's Pneumoconiosis)
a. "Black Lung"
b. About 5% prevalence among coal miners
c. Nodules, obstructive changes, PMF

4. Byssinosis
a. "Brown lung," "Monday morning asthma"
b. Acute and chronic airways disease
c. Affects workers with dusts of cotton, flax, hemp
d. Picking, blending, carding > spinning, weaving
e. 35K retired and current textile workers have significant disability

5. Occupational asthma
a. May be immunologic or nonimmunologic
b. Grain dusts, flour, metals, inorganic chemicals, isocyanates, enzymes, fungi

6. Lung cancer
a. Arsenic, asbestos, chloroethers, chromates, ionizing radiation, nickel, PAH's
b. Clinically just like other lung cancers, i.e. smoking-related cases

B. Musculoskeletal injuries

1. Major examples
a. Low back injuries
b. Repetitive motion-associated trauma: carpal tunnel syndrome (CTS), tendonitis
c. Vibration-associated injuries: whole-body vibration vs. segmental vibration

2. Important because of preventability through job redesign, principally through the use of ergonomic principles.

C. Occupational cancer

1. Examples:

Examples of Occupational Cancers
ICD-9ConditionIndustry/OccupationAgent
151Stomach CancerCoal minersCoal dust
155Liver hemangiosarcomaVinyl chloride productionVinyl chloride
160Nasal cancerWoodworkers, cabinetmakers
Boot & shoe producers
Radium workers
Nickel smelting & refining
Wood dust
Unknown
Radium
Nickel
161Laryngeal cancerAsbestos workersAsbestos
158, 63Mesothelioma of pleura, peritoneumAsbestos workersAsbestos
170Bone cancerRadium workersRadium
187Scrotum cancerLathe & metal workers
Coke oven workers, petroleum refiners, tar distillers
Cutting oils
Soots, tars, tar distillates
188Bladder cancerRubber and dye workersBenzidine, beta-naphthylamine, & derivatives
189Renal cancerCoke oven workersCoke oven emissions
204Leukemia, lymphocyticRubber industry
Radiologists
Unknown
Radiation
205Leukemia, myelocyticMany
Radiologists
Benzene
Radiation
207ErythroleukemiaManyBenzene

.
2. Occupational cancer can be challenging for both the clinician and the epidemiologist because:
a. it occurs years after exposure (the principle of latency)
b. people can be exposed to multiple carcinogens on the job
c. people can be exposed to carcinogens in the general environment and through lifestyle (e.g. smoking)
d. many occupational cancers are clinically identical to nonoccupational cancers
e. clusters are difficult to study

D. Major trauma

1. NIOSH estimates 10 million/yr, 3 million severe, at least 10,000 fatal

2. Death: Highest incidence in mining, agriculture, construction. 34% overall are MVA's.

3. Amputations: 93% fingers

4. Fractures

5. Eye loss

6. Lacerations

E. Cardiovascular disease:
The American Heart Association lists six environmental factors with potential impact on cardiovascular disease: water hardness, trace elements, occupational inhalants, CO, noise and radiofrequency, physical and psychosocial stress. Of these, three are relevant in the occupational setting:

1. Chemical exposures
a. Carbon monoxide (CO): asphyxia
b. Carbon disulfide (CS2): hypertension, atherosclerosis
c. Halogenated hydrocarbons: sudden death, probably due to arrhythmias
d. Nitroglycerin and nitrates: rebound vasospasm

2. Noise: HTN

3. Psychosocial stress

F. Disorders of reproduction

1. Multiple adverse outcomes possible:
a. Maternal factors: irregular menses, decreased fertility, increased miscarriage rates.
b. Paternal factors: sperm abnormalities, decreased fertility.
c. Fetal factors: birth defects, developmental abnormalities, subsequent cancers.

2. Examples of known reproductive toxins:
a. Lead: Increased miscarriage rates among exposed pregnant women, semen abnormalities among exposed men, impaired neuropsychological development among offspring.
b. Methylmercury: Teratogenesis.
c. Dibromochloropropane: Male sterility.

G. Neurotoxic disorders

1. Peripheral neuropathy: Pb, Hg, CS2, n-hexane

2. Toxic encephalitis: DMAPN, pesticides

3. Psychosis: CS2, Mn

4. Extreme personality changes

5. Parkinsonism: Mn

H. Psychologic disorders

1. Neuroses

2. Personality disorders

3. Alcoholism

4. Drug dependency

I. Noise-induced hearing loss

1. Very preventable, both with early screening and with primary prevention.

2. Insidious onset, conversation loss later.

3. 10 million US workers affected.

J. Dermatologic conditions

1. Contact dermatitis

2. Chloracne: cutting oils, PCB's, dioxin

3. Heat and chemical burns

4. Abrasions

K. Infectious diseases: Mostly of interest with respect to agricultural workers, animal handlers, and health care workers.

1. Hepatitis B: health care workers should be vaccinated

2. AIDS

3. Tuberculosis: partly a problem because unrecognized. HC workers should be screened regularly

4. Influenza: receive it from patients, transmit it to patients

5. Other viral infections: rubella (15% of women of childbearing age are susceptible), CMV.

6. The rare and exotic: tularemia, brucellosis, psittacosis, etc.


III. GETTING THE INFORMATION YOU NEED

A. Taking an occupational history

1. The important questions to ask
a. A description of all jobs held
b. The exposures on the job
c. The timing of the patient's symptoms
d. Symptoms or illnesses among coworkers
e. Non-work exposures and other factors

2. When to take an occupational history
a. Respiratory disease
b. Skin disease
c. Neuropsychiatric disease including dementia
d. Hearing loss
e. Back and joint symptoms
f. Cancer
g. Exacerbation of coronary artery disease
h. Liver disease
i. Illnesses of unknown cause

3. Be humble! You might not understand everything your patient tells you, but don't be afraid to ask

B. How to get further information about what you hear:

1. Getting the generic names of chemicals:
a. The Material Safety Data Sheet
b. Contact the manufacturer
c. The Poison Control Center (589-4400 in Atlanta)
d. The National Institute for Occupational Safety and Health (NIOSH)
e. Reference books (e.g. Clinical Toxicology of Commercial Products)

2. Researching the effects of chemicals:
a. Reference books (e.g. Medical Toxicology by Ellenhorn and Barceloux, Hazardous Materials Toxicology by Sullivan and Krieger)
b.Computer searches: Medline, Toxline, Toxnet, and other data bases, both on-line and on CD-ROM.
c. Call the local occupational medicine specialist.


IV. PREVENTIVE STRATEGIES IN OCCUPATIONAL SAFETY AND HEALTH

A. Substitution of hazardous exposure with less hazardous exposure, e.g. substitute toluene for benzene

B. Engineering changes, e.g. automatic hopper loading with vinyl chloride instead of hand-loading

C. Equipment redesign, e.g. change in height of work station

D. Job redesign, e.g. have two workers, not one worker, unload heavy textile roll

E. Personnel policies, e.g. worker rotation

F. Personal protective equipment, e.g. respirators

G. Worker selection: note serious risk of discrimination, nonabatement of hazards


V. LEGAL AND ADMINISTRATIVE ARRANGEMENTS

A. Federal: The OSHAct of 1970 set forth the right of every working man and woman to safe and healthful working conditions, and established OSHA and NIOSH.

1. OSHA
a. A branch of the Department of Labor.
b. Sets and enforces standards.
c. Initially adopted a large number of consensus standards, and has added about 20 more, always embroiled in political conflict and courtroom combat.
d. Permits states to administer their own OSH programs, as long as these are at least as stringent as Federal standards.
e. Many workers not covered: self-employed workers, those in companies with ten or fewer employees, family-owned farms, state and local governments, establishments covered by other statutes, and the Federal government.
f. OSHA enforces through inspections and fines, which are becoming distinctly less common since the last election.

2. NIOSH
a. A branch of HHS, part of CDC.
b. Investigates, studies, and suggests standards.

B. State

1. Worker's compensation
a. Historical background: formed in the 1910's and 20's on state level in response to increasing numbers of tort suits against employers in the nation's industries.
b. Designed to replace lost wages, cover medical expenses and rehabilitation costs, on a no-fault basis. The accident or illness need only have been contracted at work.
c. Workers gave up the right to sue their employers.
d. Benefits: rapid coverage for injuries, theoretical incentive for companies to prevent the occurrence of compensable injuries, theoretical security for companies against unpredictably large settlements.
e. Problems: proving causation, long delays, inadequate wage replacement, very high costs for employers
f. Result: among those disabled from occupational diseases, according to Federal estimates, only 5% are supported by WC. The major sources are Social Security (53%), pensions (21%), veterans benefits (17%), and welfare (16%).
g. The role of third-party suits.

2. Other activities, e.g. Right To Know

C. Union activities

D. Management activities

E. Insurance companies

F. NGO's

1. Professional organizations.

2. Industrial organizations.


VI. CURRENT ISSUES AND FUTURE DIRECTIONS

A. Individual susceptibility and the ADA

1. The term "hypersensitivity" has many meanings, both to physicians and to the lay public.

2. The focus of much current attention, particularly in view of the human genome project, and with growing evidence that some individuals are genetically predisposed to certain conditions e.g. berylliosis.

3. Reasons for ethical and legal concern:
a. The possibility of discriminating against susceptible workers in violation of ADA
b. "Hypersensitivity" may actually reflect a reaction that is more common than not, e.g. epoxy workers and resin sensitization (75%), TDI workers.
c. May distract us from developing effective engineering changes by focusing on susceptible workers instead.
d. The tests that establish hypersensitivity are in many cases of unknown sensitivity, specificity, and clinical significance, e.g. USAF and sickle trait.

B. Changing profiles of diseases, including some that are poorly understood:

1. Upper extremity disorders

2. Multiple chemical sensitivity


C. Hazards of new technologies such as electronics, biotechnology

D. Occupational health under health care reform

E. Workplace health promotion

F. The impact of increasing international trade and economic integration on occupational health: the maquiladora industry, NAFTA, and GATT


VII. SOURCES OF INFORMATION

A. Texts:

LaDou, Occupational Medicine (Norwalk CT: Lange, 1990). (PAPERBACK)
Levy and Wegman, Occupational Health, Third Edition (Boston: Little, Brown, 1994) (PAPERBACK)
McCunney, A Practical Approach to Occupational and Environmental Medicine (Boston: Little, Brown, 1994) (PAPERBACK)
Rosenstock and Cullen, Textbook of Clinical Occupational and Environmental Medicine (Philadelphia: Saunders, 1994)
Rom, Environmental and Occupational Medicine. Second Edition (Boston: Little, Brown, 1992)
Zenz, Occupational Medicine: Principles and Practical Applications, Third Edition (Chicago: Year Book Medical Publishers, 1994)
International Labour Organization, Encyclopedia of Occupational Health and Safety (Fourth Edition, Geneva, 1995)

B. Journals:

American Journal of Industrial Medicine
Occupational and Environmental Medicine
Scandinavian Journal of Work, Environment and Health
Journal of Occupational and Environmental Medicine
International Journal of Environmental and Occupational Health






This document was last modified on 06/14/2000 03:07:50 PM



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