Methane leaks at oil sites are toxic

Large emissions of the greenhouse gas also carry a mixture of air pollutants, study finds.

- Tony BRISCOE

METHANE is an odorless, invisible gas, and leaks of it are virtually impossible to detect without specialized equipment. Above, an oil pump jack in Bakersfield.

Large methane leaks at oil and gas facilities across the United States not only unleash massive plumes of the potent greenhouse gas, but also carry a toxic mix of air pollutants that jeopardize the health of communities nearby, according to newresearch.

Over the course of 20 years, methane is capable of warming the atmosphere around 80 times more than carbon dioxide. Yet when methane seeps out of fossil-fuel extraction wells or storage tanks, it’s almost always commingled with a medley of toxic chemicals, such as cancer-causing benzene, according to a new analysis by PSE Healthy Energy.

A new interactive map launched this week by the Oakland-based nonprofit research institute examines the health risk associated with more than 1,300 large methane releases nationwide, including 32 in California, that occurred from 2016 to 2025. The tool estimates the concentrations of airborne pollutants and outlines at-risk areas.

Researchers say more than 126,000 people lived within two miles of these large methane leaks, sometimes referred to as "superemitter" events, across the country, including roughly 24,100 Californians. And in almost every case, the levels of benzene the most toxic hazardous pollutant associated with methane leaks exceeded California's health risk benchmarks.