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Study Shows Gas Stoves Leak Toxins When Not in Use

a gas stovetop
A new study shows that natural gas stoves might be more dangerous than previously thought. 
Sarah Tew/CNET

This story is part of Home Tips, CNET's collection of practical advice for getting the most out of your home, inside and out.

What's happening

A new study shows natural gas to contain more carcinogens than previously thought. The same study found that about 5% of stoves leak small amounts of gas when not in use.

Why it matters

While more research is needed to nail down the dangers, these findings could mean your gas stove is emitting harmful amounts of airborne toxins into your home.

What's next

We've provided some easy ways to mitigate risk while we wait for more conclusive results on exposure levels and health risks associated with the study's findings.

A new study from Harvard's T.H. Chan School of Public Health found that natural gas used in homes contains more toxins than previously thought. It also shows that gas-powered kitchen stoves often leak low levels of potentially harmful gas, even when they're not on. 

The 16-month study published on June 28 in the journal Environmental Science & Technology took samples from 69 stoves in homes serviced by three different natural gas companies across the Boston area. Testing of the precombustion (unburned) methane gas found over 300 chemicals, including 21 airborne toxins. Those toxins notably included low levels of benzene, a known carcinogen, which was discovered in 95% of the natural gas tested.

person testing gas stove holding a monitoring device

The study looked at the makeup of natural gas along with how much stoves are leaking when not in use. 

Brett Tyron

The study also found that about one in 20 stoves (5%) had gas leakage when not in use that was sizable enough to recommend follow-up with an expert. The leaks were typically so small that they couldn't be detected by the human nose (natural gas is odorized for safety), but still could pose a potential health risk, according to Drew Michanowicz, a senior scientist at PSE Healthy Energy who worked on the study. 

It's important to note that this study was intended only to identify potential human risk in using natural gas stoves and did not measure exposure levels of said air toxics or draw any conclusions as to what effects these low levels of exposure might have on health over time.

What does this mean for you? Is your gas stove unsafe?

It's still too early to make any sweeping statements about potential health risks from using natural gas stoves. More research is needed on exposure levels for the average person living with and using a gas stove. That said, natural gas used in the stoves that were tested proved to contain more harmful gasses than previously thought -- notably benzene -- which could pose a health risk if exposure to the unburned gas is great enough. That, coupled with gas stoves often leaking gas when not in use, could result in harmful health outcomes over time.

An induction stovetop

Folks with electric or induction stoves need not worry about the risk of natural gas leaks in the kitchen.


What should you do to keep yourself safe?

While more research is needed to determine the true dangers of natural gas stoves, there are some steps you can take in the meantime to mitigate risk. 

Make sure your kitchen is well ventilated with windows. If it's not a well-ventilated space or you're not able to keep windows cracked open, consider adding a simple fan to promote airflow. Air purifiers with charcoal filters remove harmful benzene and other air toxins. A basic model costs anywhere from $100 to $150. (Check out our picks for the best air purifiers.) 

A Nest Protect

The Nest Protect smart detector will alert you if there is smoke or carbon monoxide present. 

Lindsey Turrentine/CNET

How to tell if your stove is leaking gas when not in use

While the tiny leaks detected in the study are not likely to pose an immediate threat to your health, larger leaks can. If you suspect a gas leak in your home, contact your gas utility company immediately. They will send out a technician to investigate further and take care of any potential hazards, often at no charge to you.

Use a gas detector 

A simple gas leak detector will help identify the presence of gas around your burner and give an idea roughly how much is leaking. Testing for a gas leak will give you some information to start. If there is in fact a leak, reach out to your gas company for help.

Natural gas leaks will typically release carbon monoxide into the air that can cause poisoning and even death if it reaches high enough levels. Install a carbon monoxide detector or smart smoke and CO detector like the Nest Protect to make sure your home is not at risk.

Use your nose

Natural gas is treated with an odorant to help detect leaks so if you smell that unique smell when the burners are off, you might have an issue. But if the leak is small enough, you won't be able to smell it with just your nose and it still may be doing harm over time. 

More oven intel