Second-Hand Smoke

About Second-Hand Smoke

Second-hand smoke is a mixture of particles and gases released from burning cigarettes or other tobacco products and exhaled smoke. It contains many known carcinogens, including benzene, formaldehyde, arsenic, cadmium and chromium.

Second-hand smoke causes lung cancer and heart disease, and worsens allergic reactions and asthma. There is some evidence it may cause laryngeal and pharyngeal cancers [1].

CAREX Canada estimates that approximately 418,000 Canadians are exposed to second-hand smoke at work [2].

Burden of Cancer Results

Approximately 130 lung cancers, and possibly 20 suspected laryngeal cancers and 35 suspected pharyngeal cancers among non-smokers are attributed to occupational second-hand smoke exposure each year, based on 2011 cancer statistics. This amounts to 0.6% of all lung cancers, 1.6% of all laryngeal cancers, and 2.4% of all pharyngeal cancers diagnosed annually in Canada. The cost of the newly diagnosed lung cancers alone is approximately $129 million.

Most second-hand smoke-related cancers occur among workers in the manufacturing and trade sector (see pie chart).

Exposure Reduction

Smoking bans are the most effective way of reducing second-hand smoke exposure [3]. Significant progress has been made to reduce exposure to second-hand smoke in workplaces through legislation, as well as increased awareness of health effects and population-wide changes in smoking behaviour [4].

Despite this progress, exposure to second-hand smoke still occurs in some workplaces, such as sales and services, trades, and transportation [5]. Further efforts are needed to strengthen and enforce smoke-free workplace legislation, especially in outdoor workplaces, and to promote smoking cessation programs to workers in all sectors.

Burden Resource


  1. International Agency for Research on Cancer. IARC Monographs Volume 100E: Personal habits and indoor combustions (2012).
  2. CAREX Canada. Second-Hand Smoke Occupational Exposures Profile.
  3. McNabola A, Gill LW. The Control of Environmental Tobacco Smoke: A Policy ReviewInt J Environ Res Public Health. 2009;6(2):741-758.
  4. Ontario Tobacco Research Unit. Smoke-Free Ontario Strategy Monitoring Report.
  5. Statistics Canada. Canadian Tobacco Use Monitoring Survey (CTUMS). February to December 2012. Public use data. 2013.