Second-Hand Cannabis Smoke and Vapour

Health Canada’s position is short: second-hand cannabis smoke or vapour can be harmful, especially to children. Its parents’ guidance adds that it is safest not to smoke or vape cannabis at home or in a car if a child is present. The wording is cautious because the research on second-hand cannabis exposure is still thin. This page, current to 27 October 2026, sticks to what federal and provincial health and justice pages say.

What does Health Canada say about the smoke itself?

Two statements from Health Canada are worth knowing. Its “You asked about cannabis, we answered” page says cannabis smoke contains many of the same harmful substances as tobacco smoke and can damage the lungs, and that more research is needed on second-hand effects. Its consumer information says the toxic chemicals in cannabis smoke increase the risk of heart and lung disease, and that cannabis vapour may also carry risks. Neither page gives an exposure threshold or a number for a safe level, and we did not find one on an official page.

What does it advise at home and in the car?

For households with children, Health Canada’s guidance is to avoid smoking or vaping cannabis in the home or a vehicle, especially when a child is present. The same page covers storage:

• keep all cannabis products out of children’s reach and locked away
• keep cannabis separate from regular food and drink
• choose legal products with child-resistant packaging

Edibles are a separate risk. Health Canada says many look like cookies, gummies, brownies or drinks, and a child can mistake them for a treat. If a child eats or drinks cannabis, seek medical attention right away and call 1-844-POISON-X (1-844-764-7669), or 1-800-463-5060 in Quebec. If the child loses consciousness, has trouble breathing or has a seizure, call 9-1-1 and say you suspect cannabis.

Where is cannabis smoking restricted by law?

Provinces and territories write these rules, and they differ. Two examples from official pages:

• Ontario. Holding lighted cannabis counts as smoking under the Smoke-Free Ontario Act, 2017. Smoking and vaping are banned in enclosed workplaces, enclosed public places, bar and restaurant patios, and the indoor common areas of condos and apartment buildings. Fines are $1,000 for a first offence and $5,000 for further offences.
• British Columbia. Adults can generally smoke or vape cannabis where tobacco smoking is allowed, but not in parks, playgrounds or near schools, or within six metres of air intakes, windows and doorways of public buildings and workplaces.

For tobacco and vaping rules that often decide the same question, see smoking and vaping laws by province and the second-hand smoke hub. Landlord and workplace rules are on the cannabis at work and in rental housing page.