Natural gas viewed as potential new asbestos

Exposure to particulates in the supply of natural gas is being viewed as the most significant liability risk to emerge in recent years, and has the potential to be the new asbestos for the market, Emerging Risks understands.

The concerns follow the publication of a recent major study by the Center for Climate, Health and the Global Environment at the Harvard TH Chan School of Public Health; PSE Healthy Energy, Atmospheric and Environmental Research (AER), Gas Safety Inc., Boston University, and Home Energy Efficiency Team (HEET).

The study, published in Environmental Science & Technology, suggests that natural gas used in homes throughout the Greater Boston area contains varying levels of volatile organic chemicals that when leaked are known to be toxic, linked to cancer, and can form secondary health-damaging pollutants such as particulate matter and ozone. 

“It is well-established that natural gas is a major source of methane that’s driving climate change,” said Drew Michanowicz, visiting scientist at Harvard Chan C-CHANGE and senior scientist at PSE Healthy Energy. “But most people haven’t really considered that our homes are where the pipeline ends and that when natural gas leaks it can contain health-damaging air pollutants in addition to climate pollutants.”

Researchers conducted a hazard identification study, which evaluated whether air pollutants are present in unburned natural gas, but did not evaluate human exposure to those pollutants. 

Between December 2019 and May 2021, researchers collected over 200 unburned natural gas samples from 69 unique kitchen stoves and building pipelines across Greater Boston. From these samples, researchers detected 296 unique chemical compounds, 21 of which are federally designated in the US as hazardous air pollutants. 

They also measured the concentration of odorants in consumer-grade natural gas – the chemicals that give gas its characteristic smell – and found that leaks containing about 20 parts per million methane may not have enough odorant for people to detect them. 

The paper found that consumer-grade natural gas supplied to Massachusetts contains varying levels of at least 21 different potentially hazardous air pollutants, as defined by the US Environmental Protection Agency, including benzene, toluene, ethylbenzene, xylene, and hexane.

Concentrations of hazardous air pollutants in natural gas varied depending on location and time of year, with the highest concentrations found in the winter.

Based on odorant concentrations, small leaks can be undetectable by smell – leaks up to 10 times naturally occurring levels may be undetectable, equating to a methane concentration of about 20 parts per million.

When gas leaks occur, even small amounts of hazardous air pollutants could impact indoor air quality because natural gas is used by appliances in close proximity to people, the study added, noting that persistent outdoor gas leaks located throughout the distribution system may also degrade outdoor air quality as precursors to particulate matter and ozone.

“This study shows that gas appliances like stoves and ovens can be a source of hazardous chemicals in our homes even when we’re not using them. These same chemicals are also likely to be present in leaking gas distribution systems in cities and up the supply chain,” said Jonathan Buonocore, co-author and Research Scientist at Harvard Chan C-CHANGE.

“Policymakers and utilities can better educate consumers about how natural gas is distributed to homes and the potential health risks of leaking gas appliances and leaking gas pipes under streets, and make alternatives more accessible.”

According to experts in the liability market, there is now serious concern over the findings of the study and the potential it opens up for widespread litigation – and potentially hugely significant exposures – for the casualty (re)insurance market.

The paper found that consumer-grade natural gas supplied to Massachusetts contains varying levels of at least 21 different potentially hazardous air pollutants, as defined by the US Environmental Protection Agency, including benzene, toluene, ethylbenzene, xylene, and hexane.

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