Benzene Pollution from Oil Refineries Decreased Nationally in Recent Years, yet Facilities in Gulf South Still Lag Far Behind Others

(April 14, 2026) Benzene pollution from oil refineries has decreased significantly since the U.S. Environmental Protection Agency began requiring fenceline air monitoring for it, but vast disparities in this pollution persist between states, according to new research from Environmental Defense Fund published today in Environmental Research Letters. 

Benzene pollution at refinery fencelines in Texas and Louisiana was more than five times higher than in California and Washington between 2018-2023. These disparities were not well explained by differences in refinery capacity, meaning larger refineries didn’t necessarily pollute more benzene than smaller refineries. 

The paper, “Fenceline measurements reveal regional disparities in United States refinery benzene emissions and emission sources,” is the first peer-reviewed study to examine national trends and patterns in fenceline monitoring data over multiple years at U.S. refineries. It offers compelling evidence that EPA requirements for fenceline monitoring can be an effective way to limit health-harming pollution.

“We don’t have to accept dangerously high levels of air pollution as the cost of doing business,” said Dan Peters, data scientist at EDF. “This pollution is preventable and can be controlled with existing technology. Facilities can operate more diligently and reduce their pollution to the levels already achieved by top-performing refineries. Fenceline monitoring is an important first step to understand where leaks are happening and how to fix them so that people who live and work nearby can breathe cleaner air.”

Nationally, average refinery benzene levels have dropped 50% since EPA began requiring fenceline monitoring for it. At the worst-performing refineries, benzene hotspots occurred repeatedly at the same locations, suggesting that operators did not take sufficient steps to address persistent or recurring leaks. The paper analyzes monitoring data for 119 refineries and finds that eight of the 10 dirtiest facilities were in either Texas or Louisiana, while seven of the 10 cleanest were in California or Washington. 

10 worst-performing refineries in the U.S., ranked by 2018-2023 mean net benzene

Benzene causes cancer, and no amount of it is safe for people to breathe. It causes leukemia and other blood disorders, and it can impact the immune system and cause reproductive damage.

The Trump administration has attacked pollution protections that would require similar fenceline monitoring for other industrial sectors.