The Pemex Deer Park refinery east of Houston remains the worst source of benzene air pollution among U.S. refineries, as measured by the amount of the carcinogen measured by air monitors around the perimeter of the facility, according to EPA data compiled this month by the Environmental Integrity Project.

For the year ending on June 18, 2024, the Deer Park refinery had a net annual average of 16.7 micrograms per cubic meter (µg/m³) of benzene detected by fenceline monitors, the highest of any of the 119 refineries with available data examined by EIP. That put the refinery’s benzene levels about 85 percent higher than the EPA’s “action level” for requiring cleanup of the pollutant, which is 9 µg/m³, averaged over a year.

Deer Park also had the highest levels of benzene at its perimeter the last time the Environmental Integrity Project compiled data on the subject, for the year 2023 calendar year, with that data released in May. At the end of 2023, as well as in June 2024, six refineries were over EPA’s action level, with the others being Total Petrochemicals in Port Arthur, Texas (12.7 µg/m³); the Baton Rouge Refinery in Louisiana (12 µg/m³), the Pasadena Refinery outside of Houston (12 µg/m³); ExxonMobil’s Beaumont Chemical Plant in Texas (10.9 µg/m³); and Marathon’s Galveston Bay Refinery in Texas City, Texas (9.9 µg/m³).

In general, the number of refineries exceeding EPA’s action level for benzene – which is supposed to require companies to perform a root-cause analysis and take cleanup action – has fallen by half, from 12 to six, since 2020, according to EIP’s analysis. These generally improving numbers suggest that 2015 federal regulations that requires fenceline monitoring and cleanup actions for the cancer-causing pollutant is working to reduce health risks to nearby communities.

For more on the subject, EIP’s benzene dashboard.