Shisha pipes expose users to carcinogenic benzene

In collaboration with the Press Association

US scientists have found people who smoke tobacco with shisha pipes are exposed to higher levels of a carcinogenic chemical called benzene, reinforcing the idea that there is no safe way to use tobacco.

“People who smoke shisha may think the water filtering aspect and sweet flavours disguise the potential cancer risk, but there is no safe way to use tobacco" - Nicola Smith, Cancer Research UK

Smoke from the devices may also put non-smokers at risk according to the study, which was published in the journal Cancer Epidemiology, Biomarkers & Prevention.

Shisha pipes – or hookah – are a type of tobacco pipe with a long, flexible tube which draws the smoke through water contained in a bowl. The pipes use burning charcoal to heat the tobacco in order to create the smoke which is then inhaled.

The researchers analysed urine samples from 105 shisha smokers and 103 non-smokers who went to events at dedicated ‘hookah lounges’ and shisha smoking sessions in homes.

Samples were taken the morning of, and the morning after, the events. The researchers then measured levels of S-phenylmercapturic acid (SPMA) - a marker of benzene exposure – in participants’ urine.

The team found that levels of the chemical were 4.2 times higher in shisha smokers and 2.6 times higher among non-smokers after attending an event at the hookah lounge.

Lead researcher, Professor Nada Kassem from the Centre for Behavioural Epidemiology and Community Health at San Diego State University in the US, said: “In contrast to what is believed, hookah tobacco is not a safe alternative to smoking other forms of tobacco.”

According to Kassem, there is "no safe level of exposure to benzene," and the team believe their findings could be used to aid regulation over the use of shisha tobacco.

She added that smokers and non-smokers alike who go to so-called hookah lounges also inhale "large quantities" of toxic and carcinogenic emissions generated by the burning charcoal used to heat the tobacco.

Nicola Smith, health information officer at Cancer Research UK, said that, although the study didn’t directly compare shisha smokers’ exposure to benzene with people who hadn’t been exposed to the chemical at all, the study reinforced the overall risks of tobacco smoke.

“The significant increase in exposure to benzene, a carcinogen known to cause leukaemia, in shisha smokers in this study adds to our understanding of the dangers around smoking tobacco in this way,” she said.

“People who smoke shisha may think the water filtering aspect and sweet flavours disguise the potential cancer risk, but there is no safe way to use tobacco,” she added.

The study was supported by the American Cancer Society and Flight Attendant Medical Research Institute.


  • Kassem, N., et al. (2014). Benzene Uptake in Hookah Smokers and Non-smokers Attending Hookah Social Events: Regulatory Implications Cancer Epidemiology Biomarkers & Prevention, 23 (12), 2793-2809 DOI: 10.1158/1055-9965.EPI-14-0576