Gas piped into homes contains benzene and other hazardous chemicals, study finds

Although the concentrations are low, the chemicals are potentially dangerous and some are linked to cancer risk, the researchers found.

< p class="css-at9mc1 evys1bk0">Natural gas delivered to homes contains low levels of several cancer-linked chemicals, a new study finds. Researchers also found inconsistent levels of odorants - substances that give natural gas its characteristic "rotten egg" smell - that could increase the risk of small leaks going undetected.

The study, which was published in the journal Environmental Science & Technology, adds to a growing body of research that links the delivery and use of natural gas to adverse health consequences. public health and the climate.

Most previous research has documented the pollutants present where oil and gas extraction takes place, but there is "less of studies as you move up the supply chain," said Drew Michanowicz, the study's lead author, looking at "where we actually use it, in our homes."

< p class="css-at9mc1 evys1bk0">For 16 months, researchers led by Harvard T.H. La Chan S School of Public Health collected 234 samples of unburned natural gas from 69 homes in the Boston metro area that received natural gas from three suppliers. They found 21 'air toxics' - an Environmental Protection Agency classification of hazardous pollutants known or suspected of causing cancer, birth defects or adverse environmental effects - including benzene, which was detected in 95% of samples.

Short-term exposure to high levels of benzene in particular could lead to drowsiness, dizziness, headache and irritation eyes and skin, according to the Centers for Disease Control and Prevention. Long-term exposure can increase the risk of blood disorders and certain cancers such as leukemia.

The highly flammable chemical is colorless or light yellow and is found in products made from coal and petroleum, including plastics, resins and nylon fibers, as well as certain types of rubbers, dyes and pesticides. It is also regularly found in vehicle exhaust, tobacco smoke, and gasoline.

The concentrations of benzene the researchers found in the samples of natural gas were "much lower compared to the amount in gasoline," Dr. Michanowicz said Friday in a conference call with reporters. Even so, he said, the finding is concerning since "Natural gas is used so widely in society and in our indoor spaces".

Americans spend more than 90% of their time indoors, according to the E.P.A., where concentrations of some pollutants can range two to five times higher than outdoor concentrations.

Benzene is a carcinogen, and exposure over time adds up, leading some experts to suggest there is no level of 'safe exposure.

The researchers said the purpose of their study was to identify the presence and concentration of some and that further research is needed to understand the health risks.

"The major sources of benzene in most people's lives are car gasoline and smoking," said Rob Jackson. , a Stanford University geologist who did not work on the study. "On the other hand, any unnecessary benzene in your home is just too much."

The unburned natural gas also contained inconsistent levels of odorants or substances that give off a noticeable odor, according to the researchers. Methane, the main component of natural gas, is odorless, so odorants are regularly added to help detect leaks.

"If there is less odorant in the natural gas stream, there is a higher potential for larger odorless leaks to exist,” Dr. Michanowicz said on Friday's call.

When released into the atmosphere without being burned, methane is a particularly potent greenhouse gas that can warm the planet