Hookah Secondhand Smoke: Is It Harmful to the People Around You? What Public Health Bodies Say

“I don’t smoke, but my friends invited me to a hookah lounge.” “Is it okay if people at the next table are smoking?” Many people wonder about the effect on everyone else in the room, not just the smoker.

This guide looks at hookah (also called shisha or waterpipe) secondhand smoke and passive smoking. It brings together information from public bodies such as the U.S. Centers for Disease Control and Prevention (CDC), the World Health Organization’s Regional Office for the Eastern Mediterranean (WHO EMRO), the Tokyo Metropolitan Government and Japan’s Ministry of Health, Labour and Welfare.

This article is general information, not medical advice. If you have any worries or questions about secondhand smoke or how you feel, please talk to a doctor.

What public health bodies say: at a glance

• The CDC says that secondhand hookah smoke contains not only tobacco smoke but also smoke from the heat source, such as charcoal.
• WHO EMRO says that being exposed to secondhand waterpipe smoke can also harm pregnancy.
• The Tokyo Metropolitan Government published a survey in which 22.2% of people who had been in the same space as someone using a waterpipe said they had experiences such as “feeling unwell.” Tokyo says that in an enclosed space, there is a risk of carbon monoxide poisoning not only for the person smoking but also for the people around them.
• Japan’s Ministry of Health, Labour and Welfare (e-health net) says that secondhand smoke during pregnancy is regarded as a definite factor in sudden infant death syndrome (SIDS), and that links with low birth weight and fetal growth restriction have also been pointed out.
• Japan’s Health Promotion Act means that people under 20 cannot enter smoking areas, even if they are not there to smoke.

Each point is covered in more detail below.

What makes hookah secondhand smoke different

It includes smoke from the charcoal

Hookah uses charcoal to heat the flavor. The CDC says that secondhand hookah smoke contains not only tobacco smoke but also smoke from the heat source, such as charcoal. Because the heat source differs from a cigarette’s, the smoke in the room does not come from the tobacco leaf alone.

The CDC also says that hookah smoke contains nicotine, tar and heavy metals, and that the charcoal can produce high levels of carbon monoxide, metals and cancer-causing chemicals.

The water does not filter the smoke

Some assume that smoke passing through water comes out clean. However, the CDC says that the water in a hookah does not filter the smoke. WHO EMRO likewise says that the belief that passing through water makes the smoke clean is a misconception.

Nicotine-free flavors still produce smoke and carbon monoxide

Nicotine-free flavors do not contain nicotine. However, the CDC says that the smoke from both tobacco-based hookah and herbal (nicotine-free) hookah contains harmful substances such as carbon monoxide.

As long as charcoal is used, a nicotine-free flavor still means smoke and carbon monoxide for the people nearby.

Sessions are long

According to Japan’s Consumer Affairs Agency, one hookah session burns for around an hour, and carbon monoxide is produced by the charcoal and by the burned tobacco leaf, among other things. The people sitting with the smoker spend that whole hour in the same space.

For an overview of hookah’s risks in general, including why the water does not filter the smoke and how to read “equal to so many cigarettes” comparisons, see Is Hookah Dangerous?.

The effect on non-smokers in the room: carbon monoxide

22.2% of people in the same space said they “felt unwell”

In a survey published by the Tokyo Metropolitan Government in March 2025, 36.2% of people who had used a waterpipe, and 22.2% of people who had been in the same space, said they had experiences such as “feeling unwell” or “becoming unsteady and getting injured.” Some people felt unwell even though they had not smoked themselves.

In Tokyo’s tests, a hookah in a closed room raised carbon monoxide to levels causing headaches and nausea within one to two hours. Tokyo says that in an enclosed space, there is a risk of carbon monoxide poisoning not only for the person smoking but also for the people around them.

Carbon monoxide is hard to notice

According to the Japan Poison Information Center, carbon monoxide is a gas with no color and no smell. Faint smoke or a mild smell tells you nothing about how much carbon monoxide is in the air.

The CDC and the UK’s National Health Service (NHS) list symptoms of carbon monoxide poisoning such as headache, dizziness, nausea and vomiting, weakness or tiredness, chest pain or shortness of breath, and confusion. The NHS explains that symptoms may get worse when you are in the room and improve when you leave it.

A real case

Japan’s Consumer Affairs Agency describes a case in which a customer who had used a waterpipe lost consciousness and fell just after leaving the venue, and was diagnosed with carbon monoxide poisoning. Keep in mind that symptoms can appear after you leave.

For the symptoms of carbon monoxide poisoning, what to do on the spot and when to call an ambulance, see Hookah Sickness.

People who need extra care

Pregnant people

Public bodies have said the following about secondhand smoke during pregnancy:

• WHO EMRO: waterpipe use, and exposure to secondhand waterpipe smoke, can harm pregnancy.
• The CDC: exposure to secondhand smoke during pregnancy lowers birth weight.
• Japan’s Ministry of Health, Labour and Welfare (e-health net): secondhand smoke during pregnancy is regarded as a definite factor in SIDS, and links with low birth weight and fetal growth restriction have also been pointed out.

For what public bodies say about hookah during pregnancy and breastfeeding, see Hookah While Pregnant or Breastfeeding.

Breastfeeding parents and babies

A guideline included in Japan’s Children and Families Agency’s “Support Guide for Breastfeeding and Weaning” says that smoking and secondhand smoke during pregnancy and breastfeeding affect the development of the fetus and the infant and the production of breast milk, and it asks people to seek cooperation from those around them. The CDC also lists infants among the people who are more likely to become ill from carbon monoxide.

Japan’s rule: under-20s cannot enter smoking areas

Under Japan’s revised Health Promotion Act, which came fully into force in April 2020, managers of facilities with a dedicated smoking room or a smoking-purpose room must not let anyone under 20 enter the smoking room (Health Promotion Act, Article 33, paragraph 5 and Article 35, paragraph 7). A sign stating that people under 20 are not allowed in must be displayed at the smoking room’s entrance.

The Ministry of Health, Labour and Welfare explains that people under 20 may not enter smoking areas at all, even if they are not there to smoke, and that this applies to employees as well as customers. It also states that entry by under-20s is prohibited in every type of smoking room.

This means that even if the person “won’t smoke,” is “with a parent,” or will only be around “nicotine-free hookah,” someone under 20 cannot enter a smoking area where hookah is smoked. For bringing children or babies, see Can Kids Go to a Hookah Bar in Japan?. For the legal basis of the age limit, see Hookah Age Limit in Japan.

What non-smokers and the people around them can do

If you are joining a session without smoking, public guidance suggests the following:

1. Check the ventilation. The Tokyo Metropolitan Government and the Consumer Affairs Agency call on people to check whether ventilation is adequate. Tokyo asks people to lower indoor carbon monoxide levels by running exhaust fans and opening doors and windows.
2. Don’t stay too long. One hookah session burns for around an hour (Consumer Affairs Agency), so the time you spend sitting with the smoker also tends to be long.
3. Watch for changes in how you feel. If you notice a headache, dizziness or nausea, suspect the effect of carbon monoxide, even if you have not been smoking.
4. Move to fresh air. The CDC says that if you suspect carbon monoxide poisoning, you should move to fresh air and get medical care right away.
5. Tell the people around you. Don’t put up with it alone; let your companions or the staff know, and keep an eye on how others are doing.
6. Call 119 without hesitation for serious symptoms. Japan’s Fire and Disaster Management Agency says to call 119, Japan’s number for an ambulance, without hesitation when someone is unconscious or not acting normally, or has sudden shortness of breath or difficulty breathing.

If you are pregnant, or are worried about your health, not joining is also an option. Whoever does the inviting can also consider their companions’ health and circumstances.

FAQ

If I just sit with my friends and don’t smoke, is there no effect on me?
The CDC says that secondhand hookah smoke includes smoke from the heat source, such as charcoal. In the Tokyo Metropolitan Government’s survey, 22.2% of people who had been in the same space said they had experiences such as “feeling unwell.” Not smoking does not mean there is no effect.

If the hookah is nicotine-free, is there no effect on the people around it?
It contains no nicotine, but the CDC says that the smoke from herbal (nicotine-free) hookah also contains harmful substances such as carbon monoxide. As long as charcoal is used, carbon monoxide is produced.

The smoke passes through water, so isn’t the secondhand smoke clean?
The CDC says that the water in a hookah does not filter the smoke. WHO EMRO also says that the idea that passing through water makes the smoke clean is a misconception.

A friend who was with me says they have a headache. What should we do?
People who were in the same room can also be affected by carbon monoxide (Tokyo Metropolitan Government). Everyone should move to fresh air, and anyone with symptoms should get medical care.

Can a family member under 20 sit with us?
No. Under Japan’s Health Promotion Act, people under 20 cannot enter smoking areas, even if they are not there to smoke.

Summary

• Secondhand hookah smoke contains not only tobacco smoke but also smoke from the heat source, such as charcoal (CDC).
• The water does not filter the smoke, and even nicotine-free hookah produces smoke and carbon monoxide (CDC).
• 22.2% of people who had been in the same space said they had experiences such as “feeling unwell.” In an enclosed space, the people around the smoker are also at risk of carbon monoxide poisoning (Tokyo Metropolitan Government).
• Secondhand smoke during pregnancy has been linked to SIDS, low birth weight and fetal growth restriction (e-health net).
• People under 20 cannot enter smoking areas in Japan, even if they do not smoke (Health Promotion Act).
• If you join a session, check the ventilation, and if something feels wrong, move to fresh air right away.

How it works at shisha bar IORI (Gakugei-daigaku, Tokyo)

• Ages 20+ only
• We ventilate the room thoroughly and check indoor carbon monoxide levels regularly with a CO monitor
• If anyone feels unwell, please tell our staff straight away

Menu & prices · Flavor Finder · Access

References

• Centers for Disease Control and Prevention, “Hookahs”
• Centers for Disease Control and Prevention, “Substance Use During Pregnancy”
• Centers for Disease Control and Prevention, “Carbon Monoxide Poisoning Basics”
• WHO EMRO, “Tobacco Free Initiative fact sheet: waterpipe tobacco smoking”
• NHS, “Carbon monoxide poisoning”
• Tokyo Metropolitan Government press release (March 2025), “Waterpipes (shisha) carry a risk of carbon monoxide poisoning” (Japanese)
• Consumer Affairs Agency, warning on carbon monoxide poisoning from waterpipes (May 2023) (Japanese)
• Japan Poison Information Center, “About carbon monoxide” (Japanese)
• Fire and Disaster Management Agency, “Let’s use ambulances wisely” (Japanese)
• Ministry of Health, Labour and Welfare e-health net, “Women’s smoking, secondhand smoke, and pregnancy and childbirth” (Japanese)
• Children and Families Agency, “Support Guide for Breastfeeding and Weaning” (2019 revision) (Japanese)
• e-Gov Law Search, “Health Promotion Act” (Japanese)
• Ministry of Health, Labour and Welfare, “Eliminate unwanted secondhand smoke”: key points of the revised law (Japanese)
• Ministry of Health, Labour and Welfare, “Eliminate unwanted secondhand smoke”: types of smoking rooms (Japanese)