A new study just released is saying the employees of hookah bars in New York City are being exposed to dangerous levels of second-hand smoke, according to a UPI report.

Although smoking is illegal in bars and restaurants in the city, hookah bars exist under allowances in the statue for using non-tobacco-based smoking materials.  Hookah smoking has increased in popularity, especially among teenagers who think it is safer that cigarette smoking.

For the new study, researchers selected 10 workers employed at hookah bars in New York.  They collected air samples from the bars during the shift while the workers were there, and measured for fine particulate matter, fine black carbon, carbon monoxide, and nicotine.  The workers themselves were tested before and after their shifts for things like blood pressure, heart rate, markers of smoking and second-hand smoke, inflammatory cytokines in their blood and tumor necrosis factors.

The results show the air from the bars was typical of other indoor smoking areas, and the employees had higher levels of carbon dioxide, and the numbers were proportional to the number of smokers in the bars and how many hookah were in use during the shift.  These results indicate the many of the hookah bars in New York are using tobacco-based shisha, which is smoked in water pipes.  Shisha can be made with herbs and molasses and flavored with fruit and other flavors, but it can also be tobacco-based.

New York’s Department of Health has shut down several hookah bars already in 2016 for using tobacco-based shisha, since the city’s regulation only allows them to use the molasses and herb based variety.

New York is a leader in banning smoking in public places, prohibiting smoking in taxis and work places in 1998, bars, restaurants, and enclosed spaces in 2003, and parks, beaches and Times Square in 2011.

Thomas Merrill, general counsel for the health department has reportedly said he was not surprised by the findings of the study, and he suspected the vast majority of hookah bars are using tobacco-based materials.

The study’s findings were published in the journal Tobacco Control.