How Benzene in Cigarette Smoke Can Hurt You

Benzene is a colorless, flammable liquid that is naturally present in coal tar, crude oil, and as a byproduct of volcanic eruptions and forest fires. It's also found in cigarette smoke in small amounts.

Benzene has a sweet smell and evaporates quickly when exposed to the air. It is classified by the International Agency for Research on Cancer (IARC) as a Group 1 human carcinogen.

Products That Contain Benzene

Benzene is among the 20 most widely used chemicals in production in the United States today. It's primarily used to make other chemicals and can be found in products like:

• Carpet glue, spray adhesive
• Cigarettes
• Detergents
• Dyes
• Explosives
• Furniture wax
• Nylon
  
• Pesticides
• Pharmaceuticals
• Polystyrene
  

Because benzene is a component of crude oil, it is also present in home heating oil and gasoline. Auto exhaust is responsible for the majority of benzene in outdoor air. Diesel exhaust also contains benzene.

Benzene in Cigarette Smoke

Benzene is a by-product of the combustion of tobacco in cigarettes. Exposure to cigarette smoke accounts for roughly half of all human exposure to this toxin in the United States. According to the Agency for Toxic Substances and Disease Registry (ATSDR), the average smoker takes in about 10 times more benzene (about 1.8mg) than a nonsmoker daily.

Cigarette smoke is responsible for most of the benzene present in indoor environments. Smokers and nonsmokers alike are exposed to benzene when they breathe in secondhand smoke. Benzene has also been identified in thirdhand smoke.

Effects on Human Health

According to the ATSDR, a lot of what we know about the long-term effects of benzene is from research on workplace exposure in industries that work with benzene. The 2020 Surgeon General report points to benzene as one possible mechanism for a link made previously between acute myeloid leukemia (AML) and cigarette smoking. While research regarding the effect of benzene specifically from cigarette smoke seems to be lacking, it’s best to reduce your exposure due to its associated health effects and diseases, including its carcinogenic qualities.

The intensity of benzene poisoning symptoms depends on a few factors including how much, how long, and the way you're exposed to it—whether inhaled, ingested, or through skin contact, for example.

Short exposure to benzene can lead to depression of the central nervous system and irregular heart rate. If inhaled, it can result in drowsiness, dizziness, and headaches. Benzene can also be irritating to the skin, eyes, and throat.

Long-term (a year or more) exposure to benzene can produce changes in the blood. It decreases red blood cells and damages bone marrow, putting people at risk for aplastic anemia and excessive bleeding.

Benzene is also associated with an increased risk of leukemia, specifically acute myeloid leukemia. There is concern that benzene may also contribute to acute and chronic lymphocytic leukemia, non-Hodgkin's lymphoma, and multiple myeloma. Benzene exposure can weaken the immune system because it damages white blood cells, putting people at risk for more infections.

Effects of High Levels of Exposure

Although it's rare to encounter a high dose of benzene all at once (a person would not be exposed to high levels of benzene through cigarette smoke), this level of exposure through inhalation or ingestion damages the central nervous system and can lead to some serious symptoms:

• Coma
• Convulsions
• Dizziness
• Paralysis
• Rapid breathing
• Rapid heart rate
  
• Sleepiness
  
• Tightness in the chest
• Tremors
  

High levels of exposure can even cause unconsciousness or death.

Resources for Quitting

Setting out to quit smoking can be extremely difficult, but it's so important for your health. Reducing your benzene exposure is just one reason why quitting is beneficial—not just for someone who smokes, but also for those exposed to the secondhand smoke.

Seeking support and utilizing quit aids can be helpful if you're trying to quit or help someone you know quit smoking. You can ask your healthcare provider if nicotine replacement therapy (NRT), medication, and counseling may be beneficial for you.

A Word From Verywell

To reduce your exposure to benzene, take steps to quit smoking if you currently do. Until you're successful, be sure to only smoke outside your home to reduce the risk of benzene exposure for those who live with you. It may be overwhelming to think about quitting smoking, but don't lose hope. You can do it, and the right support can really help.

Finally, if someone you know is experiencing benzene poisoning, seek immediate medical attention.