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Facts About Secondhand Marijuana Smoke

Written by Evolve's Behavioral Health Content Team​:

Alyson Orcena, LMFT, Melissa Vallas, MD, Shikha Verma, MD, Ellen Bloch, LCSW, Lianne Tendler, LMFT, Megan Johnston, LMFT
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Dangers of Secondhand Smoke

First, let’s talk about cigarettes.

Secondhand cigarette smoke is a huge health risk: nothing new there. That’s why restaurants, bars, and even nightclubs across the U.S. are smoke-free. If you’re a teenager reading this, you might not know it used to be perfectly legal and socially acceptable to smoke cigarettes virtually anywhere. Grocery stores, banks, department stores, airplanes—people were free to light up when and where they pleased. Those days are long gone, however, because scientific research proves second hand smoke is harmful.

Here’s a rundown on the negative effects of secondhand cigarette smoke:

Cancer: Secondhand cigarette smoke results in around 3,000 lung cancer deaths per year. Living with a smoker increases the probability of developing lung cancer by 20 to 30 percent.

Heart Disease: Secondhand cigarette smoke is believed to increase the chances of getting heart disease by 25 to 30 percent, and may cause as many as 46,000 deaths each year.

In children, secondhand cigarette smoke increases risk of Sudden Infant Death Syndrome (SIDS), pneumonia, bronchitis, and asthma.

Here’s another fact to drive home the risks of secondhand smoke: The National Cancer Institute concludes definitively “there is no safe level of exposure to secondhand smoke.”

Think about that the next time someone around you lights up—then walk away.

Secondhand Marijuana Smoke

If you’re in recovery from addiction or substance abuse, let’s start with the obvious: it’s not a good idea to be around people smoking weed. You know this from your therapists, recovery counselors, peers, and recovery partners in 12-Step groups. Sometimes, however, you find yourself in a situation you didn’t anticipate. You end up at a party, in a car, or at an outdoor music festival, and suddenly you realize people around you are smoking.

What are you supposed to do? Should you worry? Will you get high? Will you fail a drug test even if you don’t smoke anything?

We’ll answer those questions one at a time:

What are you supposed to do?

Leave. If you’re at a party, get outside. If you’re in a car, ask to be dropped off somewhere safe. If you’re in an outdoor situation, simply walk away. Remove yourself before you get triggered, before you’re tempted, and before you unintentionally inhale any smoke. If you’re with friends, they’ll understand. If they don’t, then perhaps it’s time to re-evaluate that friendship.

Should you worry?

Don’t freak out. But don’t take it lightly, either. Worry may not be the right word—let’s use another phrase: be actively concerned. And you should definitely question the decision-making process that got you in that position in the first place.

Will you get high?


Research shows this depends on the quality of the air circulation. If you’re in a closed room with poor or no ventilation, you may experience “mild to moderate” sedative or euphoric effects. If you’re in a well-ventilated area, you’re unlikely to feel anything.

Will you fail a drug test even if you’re not smoking?

You might.

Again, it all depends on the quality of the air circulation. The same study cited above reports that if you’re in a room with poor or no ventilation, secondhand marijuana smoke can “produce detectable cannabinoid levels in blood and urine.” If you’re in a well-ventilated area, the cannabinoid levels in your blood are unlikely to produce positive blood or urine test results.

The Bottom Line

Secondhand smoke of any kind is bad for your health. Don’t be fooled by people who say things like “marijuana is natural and doesn’t have all those nasty chemicals cigarette smoke has.” Don’t ever let anyone try to tell you that hot smoke in your lungs is nothing to worry about: that’s absurd, and it’s beside the point, anyway.

When you’re in recovery or treatment for addiction or substance abuse, the point is to avoid any situation where people are doing drugs, period. This includes any situation where you may be exposed to secondhand marijuana smoke. The negative consequences are too great to risk:

  1. You might get triggered and relapse.
  2. You might unintentionally get high, which may also lead to relapse.
  3. You might test positive on a drug test, which may erode trust between you and your parents, counselors, and recovery partners, and potentially cause you to lose privileges you’ve worked hard to earn while in rehab.

You know you’re responsible for your own actions, and if, for whatever reason, you find yourself in a position where you’re exposed to secondhand marijuana smoke, you know you’re accountable for any consequences that may follow. The best way to handle it is to be proactive and honest with anyone directly involved with your treatment and recovery. Don’t try to hide it or hope nothing shows up. Use it as a teachable moment. Learn from the experience. Next time you’ll see it coming, and you can avoid the situation altogether.

Our Behavioral Health Content Team

We are an expert team of behavioral health professionals who are united in our commitment to adolescent recovery and well-being.

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