Press Release: 6/2/2026

Elevated indoor methane found in 93% of Massachusetts, Rhode Island homes with gas equipment, reaching as high as 20 times above outdoor levels

FOR IMMEDIATE RELEASE:

June 2, 2026

MEDIA CONTACT: 

Ali Hameed

201.285.9649

Ali.Hameed@sunstonestrategies.org

 

 

In survey of 175 homes with gas services, researchers found average methane concentration more than four times outdoor levels in 20% of homes with the highest indoor methane levels, while one home recorded 38.2 ppm of methane over outdoor levels

 

BOSTON – New England residents who live with gas equipment are more likely to live with elevated indoor levels of methane compared to homes without gas, raising questions around the exposure to toxic elements of methane, according to a recently published paper in PLOS One. Boston University and Gas Safety, Inc. researchers tested indoor methane levels in 195 homes in Rhode Island and Massachusetts, finding that 93% of homes with gas service had higher methane concentrations than all-electric homes. In the 20% of homes with the highest indoor methane concentrations, researchers found an average of 8.4 ppm of methane, more than four times outdoor levels, reaching as high as 38.2 ppm. 

 

“As part of the largest such study to date in New England, testing of indoor air in Massachusetts homes has shown that the use of gas equipment – and in fact even the mere presence of gas piping – results in significantly elevated levels of methane gas in most homes,” said Lisa Cunningham, Director at ZeroCarbonMA. “This report should be a wakeup call for  policymakers. Burning methane gas adversely affects our health, pollutes our air, and worsens our climate crisis. Massachusetts policymakers must take immediate action to accelerate the adoption of clean and efficient, all-electric technology.” 

 

The paper, Indoor methane consistently above outdoor levels in homes with natural gas service, detected elevated methane levels in all kinds of homes independent of age, type or size. While the highest levels of methane gas were found in basements, elevated concentrations were also found on first, second, and third floors. In contrast, indoor methane levels of all-electric homes had the same level of methane as ambient outdoor air. In 91% of the homes with elevated methane, researchers identified the source of the leaks to gas pipes or equipment.

 

“This study adds to the growing evidence that many households in the Commonwealth are exposed to elevated indoor levels of methane.” said Andee Krasner, a public health consultant and volunteer with Mothers Out Front. “It raises questions about how many people are unknowingly being exposed to unhealthy carcinogens found in methane gas, like benzene, and what the health impacts are.”

 

If focused, many people can typically smell a gas leak at 3 ppm, aka more than 1 ppm above the ambient background of 2 ppm. However, residents who live with low levels of methane gas may not be able to detect a gas leak because they have grown accustomed to the smell or may have a weakened or no sense of smell due to advanced age or a COVID-19 infection. Living with elevated methane levels can pose health risks, as methane gas contains a number of health-harming pollutants such as benzene, toluene and xylene (BTX). Benzene is a known carcinogen linked to blood cancers which has no safe exposure level according to the World Health Organization. 

 

“Our research shows that methane is leaking indoors in the vast majority of homes served by gas,” said Nathan Phillips, Boston University professor and report co-author. “This finding should guide policymakers as they consider future spending on the gas system, which only perpetuates the harmful effects of methane leaks. Helping households adopt state-of-the-art technology such as electric heat pumps can increase affordability and improve health outcomes for Massachusetts residents while reducing climate-warming emissions.” 

 

Methane, which is over 80 times more potent than carbon dioxide, is a greenhouse gas responsible for supercharging the climate crisis. In 2021, 11,624 gas leaks in streets across Massachusetts emitted nearly 7,000 metric tons of methane—equal to the energy consumed by more than 80,000 homes in one year. In Massachusetts, buildings alone account for 35% of greenhouse gas emissions, largely due to the continued use of fossil fuels. At higher levels, methane leaks also pose a safety threat to families. A study from PSE Healthy Energy shows that Boston firefighters responded to 570 dangerous gas leak incidents in 2018 alone, costing taxpayers $2.6 million. 

 

“As long as Massachusetts continues to rely on methane gas for home heating, Massachusetts families will pay the price with their health and safety,” concluded Cunningham. “We have the tools to build healthier, more affordable homes. It’s past time we invest in them.” 

 

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About ZeroCarbonMA:

ZeroCarbonMA is committed to working in collaboration with communities across Massachusetts to implement practical and impactful climate policies based on health, equity, and affordability, while expanding our collective reach to the State and National level. Find out more at https://www.zerocarbonma.org.

 

Gas Safety, Inc. 

Gas Safety Inc is committed to the safe transmission and use of natural gas. Natural gas leaks can be an explosion hazard as well as an environmental hazard that can threaten your health and environment. Natural gas leaks emanating from distribution piping systems are causing millions of dollars of damage to lawns, shrubs and trees.  Our instruments have the ability to detect as little as 1 part per billion of natural gas or propane. Gas Safety employees are operator qualified to conduct Department of Transportation compliance leakage surveys and to respond to odor complaints.