This study questions the analysis of U.S. OSHA about their risk assessment on second hand smoke in the workplace. We do not editorialize this study. Its comments and conclusions speak for themselves.

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ABSTRACT

In response to a request for information on indoor air quality problems, the U.S. Occupational Health and Safety Administration (OSHA) has proposed a rule addressing indoor air quality in general, and especially environmental tobacco smoke (ETS), in indoor work environments. As justification for the proposed rule, OSHA relies on a quantitative risk assessment used to provide estimates of lifetime risk of lung cancer and heart disease associated with workplace exposure to ETS. However, there are a number of concerns regarding the OSHA risk assessment.

The form of underlying mathematical model used in the risk assessment is inappropriate. OSHA was highly selective in choosing what data values to use in their risk assessment. Many data values required as input to the OSHA risk assessment model are simply not known at this time. When such values as required, known, but possibly inappropriate, values were substituted. The conclusions arrived at by OSHA on the basis of this risk assessment seem unwarranted.

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Lung Cancer - Table 3 presents results from 13 studies reporting relative lung cancer risk associated with workplace ETS exposure. Where studies present estimates for males and females separately, both estimates appear in the table. Only three of these risks achieve borderline statistical significance.

How appropriate is it to use a parameter estimate from a single study when there are many published estimators available? A number of choices were available as estimators for the relative lung cancer risk parameter; why choose one over the other? Fontham et al's (1991) estimate of 1.34 is the third highest among the 17 RRs presented in Table 3 and is the second highest among the 10 U.S. RRs. Because the lifetime occupational cancer risk given by the model increases with the relative lung cancer risk [Eqs. (2) and (3)], the magnitude of the relative risk estimator used can have a dramatic impact on the results of the risk assessment.

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Heart disease - In contrast to the case of lung cancer, there are only very limited results available for relative heart disease mortality risk associated with workplace ETS exposure. [...]

1. Occupation and economic factors are so heavily confounded with smoking patterns that the presence of a smoking male in the household acts as a surrogate for para-occupational exposure (i.e.: exposure of household members to toxic substances brought home from the workplace on the skin, hair, and clothing of employed, especially blue-collar persons) of other household members.

2. There are many observations of a firm link between paternal and spousal occupations and disease of other members of the household, especially for wives and children of industrial workers.

3. Many persons exposed to carcinogens and other toxic materials in the workplace bring these materials home on their person, thereby exposing other household members.

4. There is a strong association between socioeconomic status and mortality.

5. Nonsmoking wives of nonsmokers have been observed to have "healthier" lifestyles in general than do nonsmoking wives of smokers.

6. Elevated risks have been reported for nonsmoking females living with smoking males but not for nonsmoking males living with smoking females.

7. Studies of the effects of workplace exposure to ETS in general have been negative.

Until and unless this confounding between socioeconomic factors and ETS can be resolved there is no justification to use relative heart disease risk obtained from spousal studies for estimating relative heart disease risk due to the ETS exposure in the workplace.

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CONCLUSIONS

Does OSHA risk assessment withstand scrutiny as a scientific document? As discussed previously, their analysis contains a number of serious flaws.

In a recently reported criticism of the way federal agencies have implemented risk assessment, the Office of Management and Budget made a number of specific recommandations, including (Haimea et al., 1994)

• 1. Studies showing positive relationship should not outweigh those showing no relationship.
• 2. Decision makers should be provided with expected, unbiased risk, estimates of uncertainty, and outdoor ranges of potential risk.
• 3. A renewed effort must be made to separate science from policy.

In performing their workpplace ETS risk assessment, OSHA was under considerable pressure to arrive at conclusions similar to those arrived by other government agencies such as the Surgeon General and the EPA. It is not the conclusion themselves that are at issue here, but rather the means OSHA used to justify those conclusions.

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