Cancer Trends Progress Report

Secondhand smoke (SHS) is a mixture of the sidestream smoke released by a smoldering cigarette, pipe, hookah or waterpipe, or cigar, and the mainstream smoke exhaled by a person who smokes. SHS is a complex mixture containing thousands of chemicals, including formaldehyde, cyanide, carbon monoxide, ammonia, and nicotine. More than 250 of the chemicals in SHS are known to be harmful, and at least 69 are known to cause cancer.

Conclusive scientific evidence documents that SHS causes premature death and disease in children and adults who do not smoke. Among adults, exposure to SHS has immediate adverse effects on the cardiovascular system, and long-term exposure to SHS causes coronary heart disease, stroke, and lung cancer. Children exposed to SHS are at increased risk for sudden infant death syndrome, acute respiratory infections, middle ear disease, more severe asthma, respiratory symptoms, and slowed lung growth. 

There is no risk-free level of exposure to SHS. Eliminating smoking in indoor spaces, including homes and workplaces, is the only way to fully protect people who do not smoke from exposure to SHS.

Many individuals and families, including both people who smoke and people who don’t, have voluntarily adopted smokefree rules for their homes, reflecting a change in community social norms. Studies have found that adoption of smokefree home rules is a significant predictor of smoking cessation success. For children, smoking in the home is the main source of exposure to SHS. About 80 million (1 in 4) people in the US live in multiunit housing, such as apartments, including about 7 million living in government-subsidized housing. Secondhand smoke can travel between units and into common areas in multiunit housing. To protect nonsmokers living within public housing, the U.S. Department of Housing and Urban Development adopted a rule making all public housing smokefree. This rule was implemented in July 2018.

Smokefree laws in workplaces not only protect people from SHS exposure, but also reduce youth initiation and encourage people who smoke to quit. As of January 1, 2024, thirty-six states, along with the District of Columbia, American Samoa, Guam, the Northern Mariana Islands, Puerto Rico, and the U.S. Virgin Islands, have laws in effect that require one or more of the following venues to be 100% smokefree: non-hospitality workplaces, restaurants, bars, and state-run gambling establishments. A total of 1,194 cities and counties have a 100% smokefree provision in effect in the following venues: non-hospitality workplaces, restaurants, and bars. In 2021, the Navajo Nation become the first tribe to pass legislation to create a comprehensive commercial tobacco free environment for all public places (including the four Navajo casinos, pow wows, annual festivals, and sports and rodeos). This will protect people living within and visiting the Navajo Nation who do not smoke. 

E-cigarettes (also known as vapes or Electronic Nicotine Delivery Systems) are battery-powered devices that convert a liquid (“e-liquid”) into an aerosol. E-liquids typically contain nicotine, flavorings, vegetable glycerin, propylene glycol and other chemicals. In addition to nicotine, e-cigarette aerosol may contain heavy metals, volatile organic compounds, and fine and ultrafine particles that can be inhaled deeply into the lungs by both users and by-standers. States and localities are increasingly incorporating prohibition of e-cigarette use into comprehensive smokefree air laws. As of January 1, 2024, 27 states, including the territories of Guam, the Northern Mariana Islands, and Puerto Rico, and 1,054 municipalities have prohibited the use of e-cigarettes in 100% smokefree locations.