The Congressional Research Service Raises Questions About EPA's Secondhand Smoke Study


By Matthew C. Hoffman, CEI Policy Analyst

The Environmental Protection Agency's controversial claim that secondhand tobacco smoke causes lung cancer has met a new challenge from an unexpected source: the Congressional Research Service (CRS), the research arm of the U.S. Congress. The CRS's reputation for accuracy and impartiality adds weight to the growing skepticism about the EPA's "Passive Smoking" study, which concludes that 3,000 people die annually from exposure to other people's tobacco smoke.

According to the CRS report, "Cigarette Taxes to Fund Health Care Reform: An Economic Analysis," the EPA's study made subjective judgements, failed to account for important factors that could bias the results, and relaxed a crucial scientific standard to achieve the result the study was looking for in the first place. The CRS notes, perhaps wryly, that such problems add "uncertainty" to the study's conclusions.

To arrive at its conclusion that secondhand smoke causes lung cancer, the EPA didn't bother to do any research of its own. Instead, it looked at the results of other studies -- studies that had mostly failed to find a positive relationship between secondhand smoke and lung cancer. When the EPA didn't like the methods used by the the studies, it simply altered them. This included changing the crucial "confidence interval" used to reduce the chance of mistaking a random correlation for a true relationship. The CRS blasts EPA for this flouting of scientific procedure, remarking that "it is unusual to return to a study after the fact, lower the required significance level, and declare its results to be supportive rather than unsupportive of the effect one's theory suggests should be present."

But altering the results of the studies wasn't enough for the EPA. The CRS notes that it "also made subjective judgments about the extent to which the studies suffered from statistical problems," and ignored those studies that "fared poorly in this analysis." Two other studies that were completed after the EPA began its research were ignored as well, the CRS observes, and "the one with the largest number of observations found no overall increased risk of lung cancer among nonsmoking spouses of smokers." The other failed to achieve a statistically significant result.

The studies EPA looked at were all surveys of women married to smokers, many of them conducted over the phone. They asked the women to give a very rough estimate of their exposure. Often, the women weren't available, and an acquaintance answered the questions. Unfortunately, most of the surveys didn't gather adequate data about other factors that might bias the results ("confounding factors"), like the diet, or income of the women. "If wives of smokers share in poor health habits or other factors that could contribute to illness and that are not or cannot be controlled for, statistical associations found between disease and passive smoking could be incidental or misleading," notes the CRS.

Medical experts outside the government are raising similar questions. In a recent article on the controversy in the journal Regulation, two professors of medicine and a practicing physician analyze the EPA study in detail. They conclude that "scientific integrity was compromised, if not outright abused, by the manner in which this risk assessment was generated," and warn that "the cost to the scientific process" is great. "Will reality and fact ever catch up with political science at the EPA?"

Despite its questionable content, the EPA study is now being used in a colorful new advertising campaign against smoking. One television spot compares the death toll from secondhand smoke to the carnage of the Vietnam war. The public, understandably alarmed by such hyperbole from a seemingly reliable source, is in many states submitting silently to draconian laws that prohibit smoking almost everywhere. Now, the Clinton administration has announced plans to extend such bans to the whole nation. The EPA report may be bad science, but it is stunningly effective propaganda.

Those who see smoking as a social evil may be apt to dismiss the relaxation of scientific standards at EPA as a little white lie, a well-intentioned measure to eliminate a nasty and unhealthy habit. But if the EPA succeeds, nonsmokers may find to their chagrin that its new license extends beyond the confines of benign nannyism. Already, the EPA is rummaging through a plethora of potential domestic health hazards, including substances in the steam emitted during hot showers, and the electromagnetic fields generated by common household appliances. Allowing EPA bureaucrats into the private lives of smokers may open new vistas for "environmental protection," at the expense of individual rights.

                      1250 Connecticut Ave. NW #1250
                           Washington, DC 20036
                      202-331-1010, fax 202-331-0640
Permission to copy granted as long as these lines are left intact. To subscribe to the cei list, send a message to "The Virtual Hand: CEI's guide to the information superhighway" is available for $5. CEI's monthly newsletter, "CEI UpDate," is free to contributors of $25.

Modification date: March 07, 2004 © Copyright 2004 by Brad Cox
Served by John Companies