The Short Answer: 

Thirdhand smoke is the chemicals left behind when someone smokes tobacco. Thirdhand smoke is unhealthy for people and pets. It can stick around for a long time in homes and cars. It gets into your body if you inhale, swallow, or touch the chemicals. Getting rid of it is really hard and can cost a lot of money. 

Yes, thirdhand smoke contains toxic heavy metals, including lead, cadmium, and arsenic. Exposure to heavy metals damages cells in the body and can interfere with healthy organ function. Heavy metals in thirdhand smoke pose a serious health risk, especially for children.

The Long Answer: 

Thirdhand smoke is the chemical residue from tobacco smoke. It is also called “tobacco smoke residue” or “stale tobacco smoke.” The chemicals in thirdhand smoke are toxic to humans, especially children. Thirdhand smoke chemical residue can linger for years in dust and on household surfaces. It can also become embedded in carpets, furniture, clothes, and building materials. It is difficult and expensive to remove.

Thirdhand smoke contains not only nicotine and cancer-causing chemicals, but also toxic heavy metals such as lead, cadmium, and arsenic. Exposure to heavy metals damages cells in the body and can interfere with healthy organ function. While the presence of these metals in tobacco smoke has been known for years, only recently has it been shown that they can persist in thirdhand smoke. 

A recent study of 179 homes with smokers and young children measured nicotine in dust (a marker of thirdhand smoke) along with lead, cadmium, and arsenic. All three metals were detected in every home’s dust. Homes with higher levels of nicotine in dust also had significantly higher levels of these metals. Even after accounting for factors like the age of the home, nicotine remained one of the strongest predictors of these three heavy metals. 

The same research team estimated that in completely tobacco-free homes, dust levels would have significantly lower levels of these three heavy metals. More specifically, there would be 49% less cadmium, 87% less lead, and 38% of arsenic. These findings suggest that tobacco smoke residue is an important and underrecognized source of toxic heavy-metal exposure in indoor environments.  These findings support efforts to completely ban smoking in all indoor environments, especially multiunit housing and other settings were  children spend time.

Do you have more questions about the toxic legacy of tobacco smoke, how it affects human health, and what we can do about it? Learn more here.

Sources: 

Cleveland Clinic. (2022). Heavy metal poisoning (toxicity). https://my.clevelandclinic.org/health/diseases/23424-heavy-metal-poisoning-toxicity 

Lopez-Galvez, N., Mahabee-Gittens, M.E., Quintana, P.J.E., Merianos, A.L., Dodder, N.G., Hoh, E., Stone, L., Watanabe, K., & Matt, G.E. (2026). Environmental tobacco smoke is a major contributor to lead, cadmium, and arsenic in settled house dust. Chemosphere, 394, Article 144820. https://doi.org/10.1016/j.chemosphere.2025.144820