Researchers tested thousands of Americans to see where benzene—a dangerous chemical linked to cancer—comes from in our daily lives. They found that people who smoke cigarettes or cigars, and those who recently pumped gasoline, had higher levels of benzene in their blood and urine. This study used data from a large national health survey between 2017 and 2020, measuring specific markers that show benzene exposure. The findings suggest that both tobacco smoke and gasoline fumes are major sources of benzene exposure for Americans, which is important because reducing exposure to this chemical could help protect our health.

The Quick Take

  • What they studied: Where does benzene—a toxic chemical—come from in people’s everyday lives? Researchers looked at smoking and gas pumping as possible sources.
  • Who participated: Over 2,500 Americans aged 12 and older who participated in a national health survey between 2017 and early 2020. The group included people of different ages, backgrounds, and smoking habits.
  • Key finding: People who smoked cigarettes or cigars had significantly higher benzene levels in their blood and urine. People who had recently pumped gas also showed higher benzene in their blood. These connections were clear and measurable.
  • What it means for you: If you smoke or pump gas regularly, you’re likely exposed to benzene. While one exposure isn’t dangerous, repeated exposure over time may increase health risks. This suggests limiting smoking and minimizing time spent pumping gas could reduce your benzene exposure.

The Research Details

This study used data from the National Health and Nutrition Examination Survey (NHANES), which is like a giant health checkup of Americans. Researchers measured three different markers of benzene in people’s bodies: benzene directly in the blood, and two breakdown products found in urine. These markers act like fingerprints showing that benzene was in the body. The scientists then asked people about their recent activities—whether they smoked, pumped gas, or ate certain foods—to see which activities matched with higher benzene levels. They used statistical tools to find connections while accounting for other factors like age, diet, and metabolism that might affect benzene levels.

This approach is important because it shows real-world exposure in actual Americans, not just in laboratory settings. By measuring multiple benzene markers in the same people, researchers could confirm that the benzene really came from the sources they suspected. The study design allowed them to create estimates that represent the entire U.S. population, not just the people tested.

This study is reliable because it used a large, nationally representative sample of Americans and measured benzene using established laboratory methods. The researchers controlled for many other factors that could affect results. However, because this is a snapshot in time (not following people over years), we can see associations but can’t prove that smoking or gas pumping directly caused the benzene exposure—though the logic strongly suggests they do.

What the Results Show

The study found clear connections between smoking and benzene exposure. People who reported smoking cigarettes in the past few days had significantly higher concentrations of all three benzene markers compared to non-smokers. Cigar smokers (including those smoking little cigars) showed similar patterns. The differences were substantial—smokers had roughly 2-3 times higher benzene levels than non-smokers. Additionally, people who had recently pumped gasoline showed higher odds of having detectable benzene in their blood, suggesting that gasoline fumes are another important source of benzene exposure. Interestingly, the three different benzene markers were correlated in smokers, meaning when one was high, the others tended to be high too, confirming they all came from the same source.

The study also looked at diet as a potential benzene source but found weaker connections compared to smoking and gas pumping. This suggests that while food may contribute some benzene exposure, it’s not as significant as these other sources. The researchers noted that the benzene markers behaved differently in smokers versus non-smokers, indicating that smoking creates a distinct exposure pattern.

Previous research has shown that benzene causes cancer and comes from tobacco smoke and fossil fuels, but this study provides new evidence about how much benzene Americans actually absorb from these everyday sources. It confirms what scientists suspected and provides measurable proof using modern testing methods. The findings align with international research showing smoking as a major benzene source.

This study shows associations but cannot prove cause-and-effect because it’s a snapshot rather than following people over time. People reported their own activities, which might not be completely accurate. The study measured benzene at one point in time, so we don’t know if exposure levels stay consistent. Additionally, the study couldn’t measure all possible benzene sources, so other exposures might exist that weren’t captured.

The Bottom Line

If you smoke, reducing or quitting smoking would significantly lower your benzene exposure (high confidence). When pumping gas, try to minimize the time spent near fumes and avoid breathing them directly (moderate confidence). These changes could reduce your exposure to a chemical linked to serious health risks. General population members should be aware that these are common exposure sources.

Smokers should especially care about these findings, as they have the highest benzene exposure. People who pump gas regularly, especially gas station workers, should also pay attention. Parents should be aware that children exposed to secondhand smoke are also exposed to benzene. People concerned about cancer risk should consider these findings when making lifestyle choices.

Benzene levels in your body can drop relatively quickly after reducing exposure—within days to weeks for acute exposure. However, the long-term health benefits of reducing benzene exposure would develop over months and years as your cumulative exposure decreases.

Want to Apply This Research?

  • Track daily smoking frequency (cigarettes or cigars per day) and gas pumping occasions (number of times per week). Monitor these weekly to see if you’re reducing exposure.
  • Set a goal to reduce smoking by 25% this month, or if you pump gas, try using a fuel pump with vapor recovery or limiting pumping frequency. Use the app to log each time you avoid these activities.
  • Create a monthly dashboard showing your smoking frequency trend and gas pumping occasions. Set reminders to reduce these activities and celebrate weeks with lower exposure. Track any health improvements you notice over 3-6 months.

This research shows associations between certain activities and benzene exposure but does not provide medical advice. Benzene exposure is one of many factors affecting health. If you have concerns about benzene exposure or cancer risk, consult with a healthcare provider. This study is observational and cannot prove that smoking or gas pumping directly causes health problems, though benzene is known to be harmful. Individual health outcomes depend on many factors including genetics, overall lifestyle, and duration of exposure. Always speak with a doctor before making significant health decisions.