Scientists have found that nonsmoking restaurant and bar employees absorb a potent carcinogen—not considered safe at any level—while working in places where they had to breathe tobacco smoke from customers and co-workers. The carcinogen, NNK, is found in the body only as a result of using tobacco or breathing secondhand smoke.
Investigators at the Multnomah County Health Department and Oregon Department of Human Services report that elevated levels of NNK showed up in the urine of nonsmoking employees shortly after they encountered secondhand smoke during their shifts. Moreover, levels of NNK, which is known to cause lung cancer, increased by 6 percent for each hour of work.
"This is the first study to show increases in NNK as a result of a brief workplace exposure, and that levels of this powerful carcinogen continue to increase the longer the person works in a place where smoking is permitted. NNK is a major cancer causing agent from tobacco products—and workers should not have to be exposed to any dose of this very dangerous chemical," said Michael Stark, PhD, of the Multnomah County Health Department and the study's lead author.
"The science shows that the threat of disease from secondhand smoke is no longer a distant threat. The amount of this carcinogen increases even within a single work shift."
In a related study in the same issue of the Journal, experts in public health law note that across the country employers already are being held legally liable for exposing workers to secondhand smoke, even if state or local laws permit workplace smoking.
They warn that as scientists continue to provide evidence of harm, employers could soon face a clear choice: either voluntarily ban smoking in their workplace or face an increasing wave of costly legal actions.
"When employers who allow smoking have scientists telling them that as soon as workers get on the job, they're breathing in some of the most dangerous carcinogens around, it's time to think about whether they want to deal with that kind of liability," said Marice Ashe with the Public Health Law Program at the Public Health Institute in Oakland, CA. and the lead author of the legal analysis. "The science is making it easier and easier to persuade courts to sanction employers who continue to allow smoking."
The Stark study on the effects of workplace smoking, "The Impact of Clean Indoor Air Exemptions and Preemption on the Prevalence of a Tobacco-Specific Lung Carcinogen Among Nonsmoking Bar and Restaurant Workers," was funded by the Robert Wood Johnson Foundation's Substance Abuse Policy Research Program (SAPRP).
It followed 52 nonsmoking employees of bars and restaurants in Oregon communities where smoking is still permitted in such establishments and compared them to 32 nonsmoking bar and restaurant employees from other Oregon municipalities where smoking is prohibited by local ordinance. Researchers collected urine samples from both groups before and after their work-shifts and tested them for the tobacco produced lung carcinogen NNK.
What they found is that three out of four employees who worked in an establishment where smoking was permitted had detectable levels of NNK compared to fewer than half of the unexposed workers. In addition, exposure to tobacco smoke was associated with a three-fold increase in levels of the carcinogen.
The study also notes that the amount of NNK in employees exposed to tobacco smoke went up in direct relationship to the number of hours worked—by 6 percent an hour on average—giving the researchers "confidence that the levels (of NNK) reported in this study do, indeed, reflect workplace exposure."
The investigators also note that their research supports the notion that the risks of secondhand tobacco smoke in the workplace are borne disproportionately by an already vulnerable group. Employees who participated in their study are typical of foodservice workers nationwide in that the majority were women, under age 30, had relatively low household incomes, and more than one third of them lacked health insurance.
"This is already a population that tends to have fewer resources to deal with health problems than many other groups so the least we can do is protect them from harmful cigarette smoke," Stark said. "For young women in particular, secondhand smoke can increase the risk of having breast cancer and of giving birth prematurely or having low-birth weight babies."
In their analysis of the legal and liability issues raised by workplace smoking hazards—"Legal Risks to Employers Allowing Smoking in the Workplace"—Ashe and her colleagues said employees harmed by secondhand smoke already are using worker compensation laws, state and federal disability laws and an employer's legal responsibility to "provide a safe workplace" to take action against secondhand smoke.
While in the past such cases have not always met with success, the study notes that as the scientific evidence mounts, employers will increasingly be on the losing end.
"Employers are always talking about high costs of insurance and the need to reduce their potential liabilities," Ashe said. "Voluntarily banning smoking and supporting state and local legislation mandating smoke-free workplaces is a relatively cheap and easy way of removing a cumbersome and costly liability."