Working in an environment where smoking is allowed is especially harmful for non-smokers, as they immediately absorb a potent carcinogen that is not considered safe at any level, a study has found.
The study was carried out by researchers at the Multnomah County Health Department and Oregon Department of Human Services who found that non-smoking workers have elevated levels of the carcinogen NNK, which is found in the body only as a result of using tobacco or breathing secondhand smoke.
They also found that levels of NNK, which is known to cause lung cancer, increased by 6 percent for each hour of work.
Michael Stark, PhD, of the Multnomah County Health Department and the study's lead author said that the study was the first one to show that increases in NNK are a result of a brief workplace exposure.
"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," he said.
"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.
"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," he added.
The study followed 52 non-smoking employees of bars and restaurants in Oregon communities where smoking is still permitted in such establishments and compared them to 32 non-smoking 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.
The study is to be published in the August 2007 edition of the American Journal of Public Health.