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“Here in New York, I can go to any restaurant and it’s smoke-free,” Whelan says. “It’s great. But Mayor (Michael) Bloomberg gets up and says the ban will save 1,000 lives a year. My estimate is that it will save zero lives a year.”

“There is no debate that secondhand cigarette smoke causes lung cancer,” says Mike Kuntz, head of Smoke Free Louisville.

The group’s fight for a smoking ban in Metro Louisville is in part based on claims that, every year, secondhand smoke “is responsible for approximately 3,000 lung cancer deaths,” a statistic the group’s site says is from the Centers for Disease Control and Prevention.

But in fact, there is considerable debate about what kind of dangers are posed by secondhand smoke.

“The best way to lose an argument is to overstate your argument,” says Elizabeth Whelan, president of the American Council on Science and Health, a group she says is dedicated to “separating health fact from health hype.”

“There is overwhelming evidence that long-term exposure to secondhand smoke aggravates acute illnesses in non-smokers,” Whelan says. “There is no debate about that. When you say that you can get cancer or heart disease from secondhand smoke, the claim becomes much more tenuous.”

Whelan, who likes dining at smoke-free establishments, says secondhand smoke can make eyes water, give patrons earaches and even trigger acute reactions in those with upper-respiratory conditions.

But the cancer claims, she says, are way overblown.

“Here in New York, I can go to any restaurant and it’s smoke-free,” Whelan says. “It’s great. But Mayor (Michael) Bloomberg gets up and says the ban will save 1,000 lives a year. My estimate is that it will save zero lives a year.”

Several landmark studies on secondhand smoke and its effects have been swarmed by fierce debate, if not about the conclusions, then about the methodology, the funders of the studies and who might use the studies as a political tool.

A 1993 report from the Environmental Protection Agency declared secondhand smoke a “Group A carcinogen.”

The report itself was an analysis — a so-called “meta-analysis” — of 11 studies on secondhand smoke. Ten of those studies, says writer Michael Fumento, author of Polluted Science, a harsh critique of the EPA’s policies, found no statistically significant cancer risk from secondhand smoke. One of those studies did find such a risk.

In 1998, U.S. District Judge Thomas Osteen threw out the EPA report, ruling that the methodology was flawed.

But Osteen’s ruling was overturned on appeal.

Jacob Sullum, author of For Your Own Good: The Anti-Tobacco Crusade and the Tyranny of Public Health, says the ruling was overturned not because of its criticisms, but because a report isn’t something a judge can rule on, even if it forms the basis of later public policy.

“All the criticisms are still valid,” Sullum says.

Kuntz says Osteen was a former lobbyist for the tobacco industry.

That same year, a study commissioned by the World Health Organization was released. It found — depending on whom you believe — either an elevated cancer risk from secondhand smoke … or no increased risk at all.

At the time that study was released, news outlets had conflicting headlines about what the study actually found.

A WHO press release stated (in all-caps), “PASSIVE SMOKING DOES CAUSE LUNG CANCER, DO NOT LET THEM FOOL YOU.”

The Washington Post noted a few months after the study’s release, “A new study, by the International Agency for Research on Cancer, found no statistically significant risk to secondhand smoke. The tobacco industry accused the study’s sponsors, the World Health Organization, of trying to suppress the findings; WHO said the companies ‘completely misrepresented’ the study.”

“The tobacco industry tried to say the WHO was suppressing the study, when it was actually just going through its normal review process,” says Kuntz.

After the study was published in the Journal of the National Cancer Institute, a Reuters report, which ran in The Washington Post, carried the headline, “Slightly Higher Cancer Risk for Passive Smokers Found.”

In May of this year, the British Medical Journal published a study by two researchers that for 40 years tracked more than 35,000 non-smokers — “never smokers,” the study called them — in California, each of whom had a smoking spouse.

The researchers said their results, “do not support a causal relation between exposure to environmental tobacco smoke and tobacco-related mortality, although they do not rule out a small effect. Given the limitations of the underlying data in this and the other studies of environmental tobacco smoke and the small size of the risk, it seems premature to conclude that environmental tobacco smoke causes death from coronary heart disease and lung cancer.”

The study generated numerous letters to the journal challenging the methodology and pointing out that the authors had received funds from the tobacco industry in the final years of their research.

“The data does not distinguish between the people who were exposed to secondhand smoke and those who were not exposed to secondhand smoke,” says Patrick Jeffreys, a community advocacy representative for the American Cancer Society. “This study started in 1959, when secondhand smoke was everywhere. Pretty much everybody was exposed to secondhand smoke.”

Jeffreys, a member of Louisville’s Smoke Free Coalition, also says the researchers did not examine data beyond 1972, while the American Cancer Society’s data was gathered through 1998.

James Enstrom, one of the study’s authors, “has been trying to get into the tobacco companies’ pockets for years,” Jeffreys says. “I’ve got letters he’s written to the companies trying to get them to fund his research.”

For Jeffreys, much of the debate surrounding studies of the dangers of secondhand smoke ignores one critical factor.

“There is a handful — out of hundreds of studies — that question the effects of secondhand smoke,” Jeffreys says. “You can either believe two or three scientists or more than a hundred scientists.”