Exposure to Secondhand Smoke from Marijuana is Dangerous

July 6, 2021

Call it what you want: marijuana, pot, weed, herb, ganja or cannabis. Regardless of the name, secondhand smoke from marijuana is dangerous for people exposed to it, especially children.1 2

In November 2016, marijuana became legal for recreational use by adults 21 and older in California. While there is a lot of research underway about marijuana and potential health benefits and harms, one thing is very clear: marijuana secondhand smoke is harmful to people around it.

Marijuana secondhand smoke is dangerous, containing many of the same cancer-causing chemicals and toxic chemicals as cigarette secondhand smoke.

It has significantly higher amounts of toxic chemicals such as tar and ammonia, and more than twice the amount of hydrogen cyanide, an extremely poisonous chemical.3 4 When you inhale the smoke, you are inhaling into your lungs some of the same hazardous fine particulates found in cigarette smoke.3

While they are different products, both marijuana and cigarettes produce harmful and toxic secondhand smoke associated with adverse cardiovascular effects like hardening and narrowing of the arteries which could lead to heart attack and stroke.5 And, unlike traditional tobacco products, research confirms that exposure to secondhand marijuana smoke produces a secondhand high.6

Studies have also shown that: Nonsmokers exposed to secondhand marijuana smoke report feeling the effects of a secondhand high, or “contact high,” 6 with detectable levels tetrahydrocannabinol (THC) – the psychoactive ingredient in marijuana– found in their blood and urine.7

Nonsmokers exposed to marijuana secondhand smoke in a room without ventilation tested positive for THC for up to three hours following exposure.8 Marijuana secondhand high effect is particularly troubling when considering the potential impact to children exposed to marijuana smoke.

Unfortunately, reports of marijuana secondhand smoke exposure are on the increase in California. A 2018 statewide survey found that adult exposure to marijuana secondhand smoke often occurs in public spaces, including sidewalks, parks, and shopping areas as well as private homes. In addition, 40% of adult Californians reported recent exposure to marijuana secondhand smoke in 2018, almost doubling in just two years.9 The potential harm from marijuana secondhand smoke exposure highlights the importance of understanding marijuana use law in California:

  1. First, while it is legal to consume marijuana on private property, you cannot consume, smoke, or vape cannabis in public places or in any location where smoking tobacco is prohibited. This may also include apartments.10 11
  2. Property owners and landlords have the right to prohibit smoking of marijuana on their properties.11 12
  3. Even though it is legal under California law, you cannot consume or possess cannabis on federal lands such as national parks, even if the park is in California.13
  4. It is illegal to take marijuana across state lines, even if you are traveling to another state where it is legal.14 15

Visit Let’s Talk Cannabis to understand the facts about marijuana use.

If you want to find out what your city is doing to protect you and your community from toxic secondhand smoke exposure, visit SecondhandDangers.org and enter your city’s name.

References renameme

  1. Wilson KM, Torok MR, Wei B, et al. Marijuana and Tobacco Coexposure in Hospitalized Children. Pediatrics. 2018;142(6):e20180820. doi: 10.1542/peds.2018-0820.
  2. Willis AL, Moss A, Torok M, Lowary M, Klein JD, Wilson KM. Smoke Exposure, Cytokine Levels, and Asthma Visits in Children Hospitalized for Bronchiolitis. Hosp Pediatr. 2019;9(1):46-50. doi: 10.1542/hpeds.2018-0067
  3. Office of Environmental Health Hazard Assesssment, Reproductive and Cancer Hazard Assessment Branch. Evidence on the Carcinogenity of Marijuana Smoke. Sacramento, CA: California Environmental Protection Agency;2009.
  4. Moir D, Rickert WS, Levasseur G, et al. Comparison of Mainstream and Sidestream Marijuana and Tobacco Cigarette Smoke Produced under Two Machine Smoking Conditions. Chem Res Toxicol. 2008;21(2):494-502.
  5. Wang X, Derakhshandeh R, Liu J, et al. One Minute of Marijuana Secondhand Smoke Exposure Substantially Impairs Vascular Endothelial Function. J Am Heart Assoc. 2016;5(8):e003858. Published 2016 Jul 27. doi:10.1161/JAHA.116.003858
  6. Cone EJ, Bigelow GE, Herrmann ES, et al. Non-smoker exposure to secondhand cannabis smoke. I. Urine screening and confirmation results. J Anal Toxicol. 2015;39(1):1-12. doi:10.1093/jat/bku116.
  7. Holitzki H, Dowsett LE, Spackman E, Noseworthy T, Clement F. Health effects of exposure to second- and third-hand marijuana smoke: a systematic review. CMAJ Open. 2017;5(4):E814-E822
  8. Herrmann ES, Cone EJ, Mitchell JM, et al. Non-smoker exposure to secondhand cannabis smoke II: Effect of room ventilation on the physiological, subjective, and behavioral/cognitive effects. Drug Alcohol Depend. 2015;151:194-202.
  9. California Department of Public Health. Online California Adult Tobacco Survey. Sacramento, CA: California Department of Public Health. 2018.
  10. Health and Safety Code Section 11362.45 (h). leginfo.legislature.ca.gov. Published November 8, 2016.
  11. Health and Safety Code Section 11362.3(a)(1)-(2). leginfo.legislature.ca.gov. Published November 8, 2016. Accessed December 11, 2018.
  12. Civil Code Section 1947.5. leginfo.legislature.ca.gov. Published June 9, 2016. Accessed December 11, 2018.
  13. California Department of Public Health. What is legal for adult use? Published October 17, 2017. Accessed December 11, 2018.
  14. Title 21 United States Code (USC) Controlled Substances Act Section 812. govinfo.gov. Published January 12, 2018. Accessed December 26, 2018.
  15. California Business and Professions Code 26080. leginfo.legislature.ca.gov. Published June 27, 2017. Accessed December 26, 2018.