Daylight hadn’t yet slipped from the sky above Port Arthur when the residents felt the ground shake. They quickly moved inside, shut windows and closed doors, sheltering in place until they got word that the explosion at the Valero Port Arthur Refinery was under control.
The ensuing fire, which polluted the community in a black chemical plume in late March, burned for nearly 10 hours and released chemicals into the air for over 10 days.
Incidents like this one are not uncommon for residents in Port Arthur, a Texas Gulf town wedged at the border between Texas and Louisiana. Of the 131 oil refineries in the United States, more than a quarter of them are in Texas and most line the Gulf Coast. Communities like Port Arthur, which sit on the industry’s fenceline, get the brunt of the pollution — including a highly hazardous and carcinogenic chemical found in crude oil and gas called benzene.
Texas refineries have historically generated some of the highest rates of benzene emissions in the country. An Environmental Defense Fund report, published this month in the journal Environmental Research Letters, found that from 2018 to 2023, refineries in Texas produced some of the highest emissions on average compared to those in other states. Further, the data, which was collected from air monitoring stations surrounding the facilities through the EPA’s 2015 Petroleum Refinery Sector Rule, revealed that rates of benzene emissions had little to do with the size or crude oil capacity of the refineries. Rather, researchers found that these emissions were far more dependent on state policy and facilities failing to address recurring or persistent leaks.
“In theory, capacity might explain some of the differences, but actually it’s not strongly associated with the amount of refinery benzene that was measured at the fenceline,” said Dan Peters, data scientist for the Environmental Defense Fund. “So it points to other factors that seem to be more important than just the refining activity itself.“
By their nature, refineries emit a laundry list of harmful air pollutants, including greenhouse gases like carbon dioxide and methane, as well as volatile organic compounds such as hydrogen sulfide, sulfur dioxide and benzene. However, refineries often emit much higher levels of these chemicals through leaks, explosions or fires. The incident at Port Arthur is one such example — leaking chemicals like butane, propane and benzene.
There are federal regulations to address refinery pollution through the Clean Air Act, but much of the enforcement falls to the state, said Peters. Further, in his second term in office, President Donald Trump and his administration have rolled back numerous Clean Air Act protections, granting widespread exemptions for the fossil fuel industry.
The Petroleum Rule has remained untouched so far, but the Trump administration has exempted the industry from similar rules in the past year.
“We do know that states play a really major role in enforcing regulations,” Peters said. “They’re responsible for overseeing the Clean Air Act and for permitting for many of the enforcement activities. Some states just have additional regulations.”
Benzene Monitoring
In 2015, the Environmental Protection Agency passed the Petroleum Refinery Sector Rule to better track and regulate rogue emissions from refineries. One part of the rule required all refineries in the United States to begin monitoring benzene levels around their facility perimeters.
Armed with this data, Peters and a team at EDF analyzed such benzene emissions from 2018 to 2023 and found that levels across the country dropped over time. Despite the decrease, Texas and Louisiana still had an average of five times the levels of benzene than refineries in California and Washington state.
“What we noticed were there were these persistent disparities between states that lasted over time and persisted through the end of our data in 2023 even though there was a significant decrease overall nationally,” Peters said. “Texas did go down, but it’s still much higher than the other states.”
Of the 119 refineries Peters studied, nine of the 20 worst benzene polluters were in Texas. TotalEnergies Refinery — another facility in Port Arthur — had the third highest levels of benzene in the country, according to data. Navajo Refining — an oil refinery in Eddy County, New Mexico — is the biggest offender on the list.
When analyzing the numbers at the facility level, TotalEnergies had nearly nine times the benzene emissions compared to the largest refinery in California — Marathon Los Angeles — even though TotalEnergies has a much lower crude oil capacity than Marathon.
While Marathon processed an average of 364,333 barrels of crude per day from 2018 to 2023, the facility emitted an average of 1.8 micrograms of benzene per cubic meter at the fenceline. TotalEnergies processes 120,000 less — 245,000 barrels a day — and emits an average of 18 micrograms per cubic meter at the fenceline, the data showed.
The EPA action level for fenceline benzene emissions is 9 micrograms per cubic meter. That means that anything above that limit is harmful for communities, and facilities must address the issue immediately.
In a statement, TotalEnergies said the company has “taken significant steps, including dedicating teams, following new processes and making multi-million-dollar investments, to reduce benzene emissions” and added that the overall annual average for benzene at the Port Arthur facility is currently 6.43 micrograms per cubic meter.
Navajo Refining did not respond to requests for comment from Capital & Main.
The results were not surprising to Shiv Srivastava, policy director for Fenceline Watch, a Houston-based environmental justice organization. Chemicals such as benzene are released into the communities around the petrochemical industry regularly, but community members often do not know the extent of the pollution, said Srivastava.
“Our communities in Houston have a very unique exposure rate simply because of the density of infrastructure that is co-located in our communities,” he said. “It’s not a question of if (the facilities) are going to explode or leak or flare, but a question simply when.”
Benzene, a colorless and volatile liquid with a range of acute health effects, is among the top 20 most produced chemicals by quantity in the United States. It’s found in the emissions from burning coal, exhaust from vehicles, industrial solvents, gas stations and refineries. Residents have described the odor as thickly sweet — like the smell at a gas station pump.
Srivastava pointed to a 2019 tank fire at the Intercontinental Terminal Company in the community of Deer Park near Houston that burned for three days. After officials lifted the shelter-in-place order, air pollution from benzene lasted weeks.
“It’s not just an immediate impact, but a multigenerational toxic harm that we experience because of emissions like benzene and all of these other petrochemicals,” Srivastava said.
From Monitoring to Enforcement
The data collected across the country through the Petroleum Refinery Sector Rule is the first of its kind to be gathered using the same procedures at every facility in the country. Every two weeks, the data is analyzed at a lab and then submitted to the Texas Commission on Environmental Quality and the EPA, Peters said.
“In theory, if you have the monitoring data, the first time you get that high result, you can see that something is happening over at that side of the facility,” he said. “So if you’re proactive, there’s an opportunity to address that before it happens again.”
However, Peters found that even after facilities were alerted to high levels of benzene, it didn’t always mean that operators successfully addressed the root cause of the pollution. The data showed that some monitors surrounding the facility would light up more frequently with higher levels of benzene, indicating that the issues were persistent or ongoing.
Inyang Uwak, environmental epidemiologist and research and policy director for Air Alliance Houston, said the finding falls in line with trends in state enforcement.
“Texas should be taking a more strategic effort to monitor for this hazardous air pollutant in communities that are close to industry,” Uwak said. “When you get the data, the next thing to do is investigate.”
Communities have for years had little trust in the Texas Commission on Environmental Quality to handle issues with industrial pollution. In 2025, the commission worked through only 39 complaints in a backlog of 1,432 cases, according to a new report from Public Citizen, a nonprofit advocacy organization. Of the over 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, the report showed.
In response, the Texas Commission on Environmental Quality said that complaints’ response time is prioritized by “relative threat to public health, safety or the environment” and many complaints were sent to other agencies because they “are not within the TCEQ’s jurisdiction.”
Additionally, the Texas Commission on Environmental Quality weakened the long-term air pollution guideline two decades ago. Today, Texas’ long-term exposure limit for benzene is 1.4 parts per billion, while in other states, the limit is much lower. For example, the exposure limit in Minnesota is 0.24 parts per billion and 0.03 parts per billion in Massachusetts.
Long-term exposure to benzene leads to serious and harmful effects such as immune disorders and cancer. In one case, the state of Texas published data in 2025 for Channelview — another fenceline community near Houston — showing that rates were “significantly greater than expected” for leukemia, lymphoma and other cancers. The community is also known to have high levels of benzene.
Peters said communities shouldn’t have to live like this. The findings, he said, emphasized that pollution is not actually inevitable.
“Facilities are already capable of operating much more cleanly because we can see that some of them are already doing it,” Peters said. “These facilities could be doing much better.”
