HEET began investigating the potential health impacts of natural gas in 2015, following the Aliso Canyon gas storage leak in Porter Ranch, California, widely considered the worst natural gas leak in U.S. history. When news of the leak broke, HEET collaborators Nathan Phillips, from Boston University, and Bob Ackley of Gas Safety USA, raced out to the site with a gas analyzer to measure gas levels in the streets.

Soon residents were calling HEET asking, “What’s in the gas?”

HEET began to search for answers.

We worked with colleagues to develop a novel method to sample the gas supply as it enters people’s homes—right at their stoves—and sent those samples to labs for analysis. The preliminary results identified the presence of a number of volatile organic compounds (VOCs) and supported expanding the research effort.

The scaled up ‘Home is Where the Pipeline Ends’ study was conducted by the Harvard T.H. Chan School of Public Health; HEET; PSE Healthy Energy; and Boston University. The whole team is grateful to the many participants who opened up their homes and stoves to advance science. The research found that the natural gas delivered to homes in Massachusetts consistently contains trace amounts of VOCs that have the potential to impact air quality and human health.

Contaminants in gas

The study identified over 296 unique volatile organic compounds (VOCs) present in small quantities in the gas that comes to our stoves, including 21 different known hazardous air pollutants. Two of these pollutants, benzene and toluene, are known carcinogens also contained in cigarette smoke, gasoline, paints, varnishes, nail polish, glues and adhesives.

When does gas leak from stoves? ‍

Another study of gas stoves showed that over 75% of the gas that leaked was released when the stoves were off. Another 25% was released due to incomplete combustion while cooking or when turning the stove on and off.

Emissions from burned gas

Cooking with gas produces nitrogen oxides and particulate matter, and if a stove is not well ventilated, these emissions can affect indoor air quality. Research suggests that a poorly ventilated gas stove can produce levels of nitrogen oxide exceeding EPA standards within a few minutes of turning on a stove. Both nitrogen oxides and particulate matter are associated with increased risk of asthma and triggering asthma symptoms.

Today, thanks in part to HEET’s work, the health impacts of cooking with natural gas are receiving national and international attention and continue to be studied.

“Until this study was published, there had been no independent academic research on the chemical composition of the gas delivered to our homes,” said Molly Fairchild, a study author and HEET’s Director of Healthy Homes. You can learn more in the Gas Leaks section of our website and on our timeline.

What can you do to improve your indoor air quality?

Ventilation
If your gas stove has a vent to the outdoors, turn it on whenever you’re cooking or baking. If you don’t have a vent, or the vent only recirculates into the kitchen, open a window.

Induction Stoves
Consider replacing your gas stove with an electric induction stove. Induction stovetops use a magnetic field to move electrons in your pan. The moving electrons bounce all around, creating heat through friction (the same as when you rub your hands together fast).

Induction stoves:

• Use 30–50% less energy
• Are easy to clean
• Offer precision temperature control—better than gas stoves
• Are safer than gas or electric. Because there is no open flame, they greatly reduce the risk of fire or burns, especially for the elderly or children.

Rebates available
Massachusetts residents can receive a $500 rebate from Mass Save towards replacing a gas or propane stove with an induction stove. Income-eligible residents can receive up to $840 from the Inflation Reduction Act towards replacing a gas or propane stove with either electric or induction.

Health Impacts of Cooking with Gas

There’s been a lot of media attention recently on the health impacts of gas stoves. Here’s an overview of what some of the research shows and what you can do to improve your indoor air quality.

• HEET – Understanding Cooking with Gas: Indoor Air Quality and Health
• The New York Times – Gas Piped Into Homes Contains Benzene and Other Risky Chemicals, Study Finds
• The Boston Globe – Scientists measured the pollutants coming from gas stoves in Boston. They found dangerous chemicals.
• Forbes – Latest Studies From Harvard, Et Al Show Health Hazards Of Gas Cooking
• Inside Climate News – Natural Gas Samples Taken from Boston-Area Homes Contained Numerous Toxic Compounds, a New Harvard Study Finds

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