ciation for Cancer Research (AACR)3 stated that ... incidence of lung cancer, it is logical to inquire whether .... filed in February 1985, the Public Service Alliance.
Passive smoking has no place in the workplace*
Editorial I
James L. Repacet I A recent review in CMAJ examined the evidence that exposure to tobacco smoke in the workplace is harmful to nonsmokers.' It noted that among the thousands of chemical compounds in tobacco smoke there are at least 60 known carcinogens. Some have been assigned threshold limit values (TLVs) for upper limits of safe concentration, while others are considered unsafe in any concentration.2 After reviewing the reported effects of passive smoking on health, the authors concluded that passive smoking is an occupational health hazard to nonsmokers, especially workers exposed to other chemicals in the workplace. In a recent position paper the American Association for Cancer Research (AACR)3 stated that "since there is no apparent threshold in the doseresponse between the extent of smoking and the incidence of lung cancer, it is logical to inquire whether lung cancer in nonsmokers might result from smoke-filled environments". It added: "Cigarette smoke contains many complete carcinogens, direct and indirect acting tumor initiators, tumor promotors, cocarcinogens, and mutagens. Of particular concern are metabolites of nicotine itself ... some of [which] are potent animal carcinogens." It further stated that "passively exposed individuals absorb cigarette smoke as indicated by significantly higher levels of urinary cotinine" and concluded that "the combined epidemiological and chemical evidence suggests that the biological effects of passive exposure are real"; accordingly, the AACR recommends that government should "enact and enforce legislation that restricts smoking in public
places". This raises the question as to what measures constitute effective restriction of smoking in the workplace and how their efficacy should be judged. For tobacco smoke the calculation of a *The views presented are those of the author and do not necessarily reflect the policy of the US Environmental Protection Agency.
tPolicy analyst Reprint requests to: James L. Repace, Policy analyst, US Environmental Protection Agency, 401-M St. SW, Washington, DC 20460, USA
weighted TLV is not possible.' Therefore, another approach must be used. In the case of environmental carcinogens it is the usual practice in the United States to use quantitative risk assessment to determine acceptable exposure levels. In the evaluation of industrial hazards under the US federal Toxic Substance Control Act and the Clean Air Act calculation of the risk level to the exposed population is usually based on a "unit risk" derived from an exposure-response relation for the carcinogen.4 Such a relation has been shown for ambient tobacco smoke.5 The risk is then calculated for the average exposure level and is most often expressed in terms of number of cancer deaths per year. The risk to the most exposed individuals is expressed in terms of a lifetime probability of cancer-related death and is compared with a reference level of "acceptable", or "de-minimis", risk. The level of acceptable risk varies depending on the program but is usually between 10 5 and 10-7; in other words, a 10- lifetime risk corresponds to a one-in-a-million chance of premature death. This method has been applied in the United States, where the number of deaths attributable to passive smoking has been estimated to be 5000 per year and the risk is about 5 X 10 -2 for the most exposed individuals.5 In Canada, which has one tenth the US population, the estimated number of deaths attributable to passive smoking per year would be about 500, but the risk to the most exposed individuals would be the same as that in the United States. If either the number of deaths per year or the risk to the most exposed individuals is deemed excessive, suitable technologic control measures are needed to reduce the risk to an acceptable level. Thus, with either guideline - excessive aggregate risk or excessive risk to the most exposed individuals - restrictions on public smoking are justified. What about the workplace? In a typical workplace, where there are about seven persons per 100 m2 and about one third of the workers are habitual smokers who smoke 32 cigarettes per day, the estimated carcinogenic risk to the nonsmokers would be, depending upon the ventilation, 250 to 1000 times that considered acceptable for environmental carcinogens in air, water or food.6 This risk cannot be reduced to an acceptable level by either ventilation or air cleaning. If smokers and non-
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smokers are in different areas but those areas are served by the same ventilation system, as, for example, in a large building, the background concentration of smoke recirculating in the ventilation system might still be several times the acceptable risk level. Thus, the only practical way to reduce the risk of passive smoking to an acceptable level would be to separate the smokers and nonsmokers into areas with different ventilation systems or ban smoking in the workplace altogether. Are such measures practical and enforceable? Group Health Cooperative, Seattle, Washington, which has 5000 employees and more than 100000 members, phased in a ban on smoking early this year with little difficulty (Robert Rosner: personal communication, 1985). Smoking and the sale of tobacco products have been prohibited in all Indian Health Service hospitals operated by the US Public Health Service (Leland Fairbanks: personal communication, 1985). The US Environmental Protection Agency (EPA) is moving toward a consensus that smoking in the workplace should be considered an occupational health issue; accordingly, several of its regional offices have implemented stringent rules: in the Boston EPA office smoking is banned except in two restrooms; in the Philadelphia EPA office smoking is banned except in a few vending rooms (penalties for violating this rule
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range from official reprimand to dismissal); and in the Seattle EPA office job announcements for the region notify applicants that smoking is prohibited. Regional officials report that their policies are working well (EPA Times 1985; 2 (14): 1). At EPA headquarters in Washington, according to a draft policy being circulated for internal review, smoking will be banned in most areas, including any offices or open spaces where employees object to others smoking in the same room. Employers who resist efforts to protect nonsmokers from indoor air polluted by tobacco smoke may find themselves defendants in costly legal actions: a class action suit filed on behalf of 8000 IBM employees in Florida in September 1984 sought to ban smoking at all IBM offices in Palm Beach County (The Evening Times, West Palm Beach, Oct. 5, 1984: C2); in another recent case, filed in February 1985, the Public Service Alliance of Canada entered into binding arbitration against the Department of National Health and Welfare on behalf of a worker who objected to being exposed to the carcinogenic risks from on-the-job smoking (The Globe and Mail, Toronto, Feb. 22, 1985: 4). The unquestionable facts are these: Smoking is a social disorder8 involving the inhalation of addictive toxic chemicals that ultimately cause premature death from heart disease, cancer and respiratory disease in about 50% of smokers. Nonsmokers are commonly exposed to the toxic chemicals in tobacco smoke in many workplaces. The evidence that such exposure is capable of causing disease in nonsmokers is solid and rapidly increasing. Prevention of occupational illness in workers is clearly the responsibility of employers. Passive smoking has no place in the workplace. References 1. Collishaw NE, Kirkbride J, Wigle DT: Tobacco smoke in the workplace: an occupational health hazard. Can Med Assoc J 1984; 131: 1199-1204
David Slaughter, B.Sc., M.D. CM., F.RC.P.(C) Dr. Karen Gilberg, Medical Director for Wyeth Ltd./Ltee is pleased to announce the appointment of David Slaughter, B.Sc., M.D.C.M., F.R.C.P.(C) to the position of Associate Medical Director. Dr. Slaughter is a graduate ofMcGill University with degrees in Science and Medicine specializing in Nephrology. He obtained his Fellowship in Internal Medicine in 1976. In his new position, Dr. Slaughter will be responsible for the activity of our Clinical Research programmes.
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2. American Conference of Governmental Industrial Hygienists Inc: Documentation of the Threshold Limit Values, 4th ed, Cincinnati, Ohio, 1980 3. Loeb LA, Ernster VL, Warner KE et al: Smoking and lung cancer: an overview. Cancer Res 1984; 44: 5940-5958 4. Anderson EL and Carcinogen Assessment Group of the Environmental Protection Agency: Quantitative approaches in use to assess cancer risk. Risk Anal 1983; 3: 277-295 5. Repace JL, Lowrey AH: A quantitative estimate of nonsmokers' lung cancer risk from passive smoking. Environ Int 1985; 11: 3-22 6. Repace JL: Effect of ventilation on passive smoking risk in a model workplace. In Proceedings of a Conference on Management of Atmospheres in Tightly Enclosed Spaces, Oct. 17-21, 1983, Santa Barbara, ASHRAE special publ, American
Society of Heating, Refrigeration, and Ventilating Engineers, Atlanta, Ga, 1983: 51-55 7. Repace JL, Lowrey AH: An indoor air quality standard for ambient tobacco smoke based on carcinogenic risk. NY State J Med 1985; 85: 381 --383 8. Slade ID: A disease model of cigarette use. Ibid: 294-297
