The sun had not yet come in Photographed from above Port Arthur as residents felt the ground shake. They immediately moved indoors, closed the windows and doors, and sheltered in place until word was received that the explosion at the Valero Port Arthur refinery was under control.
The fire, which broke out in late March, contaminated the area with a plume of black chemicals and burned for nearly 10 hours, releasing chemicals into the air for more than 10 days.
Incidents like this are not new to residents of Port Arthur, a town on the Texas Gulf Coast between the Texas and Louisiana borders. Of the 131 refineries in the United States, more than a quarter are located in Texas, most along the Gulf Coast. Areas like Port Arthur, located on industrial fence lines, bear the brunt of pollution, including a highly dangerous and carcinogenic chemical called benzene found in crude oil and gas.
Texas refineries have historically generated some of the highest benzene emission rates in the country. An Environmental Defense Fund report published this month in Environmental Research Letters found that from 2018 to 2023, Texas refineries produced some of the highest emissions on average compared to other states. Furthermore, data collected from air monitoring stations around facilities under the EPA’s 2015 Petroleum Refining Sector Rule revealed that benzene emission rates have little to do with refinery size or crude oil production capacity. Rather, researchers found that these emissions are largely dependent on national policies and facilities that fail to address recurrent or persistent leaks.
“In theory, production capacity might explain some of the variance, but in practice there is no strong correlation with the amount of benzene in a refinery measured at the fence line,” said Dan Peters, a data scientist at the Environmental Defense Fund. “So you’re pointing to other factors that may be more important than the refining activity itself.”
By their nature, refineries emit large amounts of harmful air pollutants, including greenhouse gases such as carbon dioxide and methane, and volatile organic compounds such as hydrogen sulfide, sulfur dioxide, and benzene. However, refineries often release much higher levels of these chemicals due to leaks, explosions, and fires. The Port Arthur accident is one example, where chemicals such as butane, propane and benzene were leaked.
Peters said federal regulations exist to address refinery pollution through the Clean Air Act, but much of the enforcement is left to the states. Additionally, during his second term, President Donald Trump and his administration rolled back numerous Clean Air Act protections and granted broad exemptions to the fossil fuel industry.
Petroleum rules have so far remained untouched, but the Trump administration exempted the industry from similar rules over the past year.
“We know that states play a very large role in enforcing regulations,” Peters said. “They are responsible for overseeing the Clean Air Act and authorizing a lot of enforcement activity. Some states just have additional regulations in place.”
Benzene monitoring
In 2015, the Environmental Protection Agency passed the Petroleum Refining Sector Rule to better track and regulate illicit emissions from refineries. Part of the rule requires all refineries in the United States to begin monitoring benzene levels around their facilities.
Armed with this data, Peters and the EDF team analyzed benzene emissions from 2018 to 2023 and found that levels across the country were decreasing over time. Despite the decline, benzene concentrations in Texas and Louisiana remained on average five times higher than refineries in California and Washington state.
“What we found is that even though there was a large overall decline nationally, there were persistent disparities between states that persisted over time and continued through 2023, when the data ends,” Peters said. “Texas has certainly gone down, but it’s still much higher than other states.”
Of the 119 refineries studied by Peters, nine of the 20 worst benzene polluters were in Texas. Another facility, the Total Energy refinery in Port Arthur, had the third-highest benzene levels in the country, according to the data. Navajo Refining, a refinery in Eddy County, New Mexico, is the biggest violator on the list.
Analyzing the numbers at the facility level, Total Energy’s benzene emissions were nearly nine times higher than Marathon Los Angeles, California’s largest refinery, even though Total Energy’s crude oil production capacity was much lower than Marathon’s.
Marathon processed an average of 364,333 barrels of crude oil per day from 2018 to 2023, but the facility emitted an average of 1.8 micrograms of benzene per cubic meter at the fence line. Data shows TotalEnergies’ throughput has fallen by 120,000 barrels to 245,000 barrels per day, emitting an average of 18 micrograms per cubic meter at the fence line.
The EPA action level for benzene emissions from fence lines is 9 micrograms per cubic meter. This means anything above that limit is harmful to the community and the facility must address this issue immediately.
TotalEnergies said in a statement that the company “has taken significant steps to reduce benzene emissions, including deploying a dedicated team, complying with new processes, and investing millions of dollars,” adding that the overall annual average for benzene at the Port Arthur facility is now 6.43 micrograms per cubic meter.
Navajo Refining did not respond to a request for comment from Capital & Main.
The results came as no surprise to Shiv Srivastava, policy director for the Houston-based environmental justice group Fenceline Watch. Chemicals such as benzene are regularly released into communities around petrochemical industries, but local residents are often unaware of the extent of the pollution, Srivastava said.
“Our community in Houston has very unique exposure rates simply because of the density of infrastructure co-located within our community,” he said. “It’s not a question of if (the facility) will explode, leak or catch fire, it’s simply a question of when.”
Benzene is a colorless, volatile liquid that has a variety of acute health effects and is among the top 20 most produced chemicals in the United States. This is found in emissions from coal combustion, vehicles, industrial solvents, gas stations, and refineries. Residents described the smell as thick and sweet, similar to the smell of gas station pumps.
Srivastava pointed to a 2019 tank fire at the Intercontinental Terminal Company in the Deer Park area near Houston that continued to burn for three days. Benzene air pollution continued for weeks even after authorities lifted shelter-in-place orders.
“This is not just an immediate impact, but a multi-generational toxic damage that we will experience from benzene and all the other petrochemical emissions,” Srivastava said.
From surveillance to enforcement
The data collected nationally through the Petroleum Refining Sector Regulation is the first to be collected using the same procedures at all facilities in the country. Peters said the data will be analyzed in a lab every two weeks and submitted to the Texas Commission on Environmental Quality and the EPA.
“Theoretically, if you have monitoring data, the first time you get such a high result, you know something is going on on that side of the facility,” he said. “So if you’re proactive, there’s an opportunity to address it before it happens again.”
But Peters found that even after a facility was alerted to high levels of benzene, it didn’t necessarily mean the operator had successfully addressed the root cause of the contamination. Data showed that some monitors around the facility frequently lit up due to high levels of benzene, indicating a persistent or ongoing problem.
Inyang Uwak, an environmental epidemiologist and director of research and policy at Air Alliance Houston, said the findings are consistent with state enforcement trends.
“Texas should take a more strategic approach to monitoring this harmful air pollutant in areas near industry,” Uwak said. “Once you have the data, the next thing to do is research.”
For years, communities had little trust in the Texas Environmental Commission, which handles industrial pollution issues. In 2025, the commission processed just 39 complaints out of a backlog of 1,432 cases, according to a new report from the nonprofit advocacy group Public Citizen. Of the more than 9,000 new complaints the agency received that year, more than half took at least 30 days to investigate, and 30% were closed without an investigation, according to the report.
In response, the Texas Commission on Environmental Quality said its response time to complaints is prioritized by “relative threats to public health, safety, and the environment,” and that many complaints are routed to other agencies because they are “beyond TCEQ’s jurisdiction.”
Additionally, the Texas Environmental Commission weakened long-term air pollution guidelines 20 years ago. Currently, the long-term exposure limit for benzene in Texas is 1.4 ppb, but limits in other states are much lower. For example, the exposure limit in Minnesota is 0.24 ppb and in Massachusetts it is 0.03 ppb.
Long-term exposure to benzene causes serious and harmful effects such as immune disorders and cancer. In one case, the state of Texas released data for Channelview (another fenceline community near Houston) in 2025 showing that rates of leukemia, lymphoma, and other cancers were “significantly higher than expected.” The area is also known to have high levels of benzene.
Peters said the community doesn’t have to live like this. He said the findings highlight that pollution is not actually inevitable.
“Facilities are already able to operate cleaner because we see some facilities already doing that,” Peters said. “These facilities could be better.”
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