In the fall of 2018, a leak at a Pasadena oil refinery led to the release of thousands of pounds of toxic pollutants, including some 8,000 pounds of cancer-causing benzene.

During that nearly 67-day stretch, the Pasadena Refining System reported its highest two-week average concentration of benzene from one of its fence-line monitors — a level that was 6.5 times above a federal guideline for short-term exposure.

The Pasadena refinery is one of 10 across the country that exceeded the Environmental Protection Agency’s action level for benzene as of Sept. 30, according to an analysis released recently by the nonprofit Environmental Integrity Project. Six of them are in Texas, including three in the Houston area.

“Benzene is the most ubiquitous hazardous air pollutant Houston has to deal with, we are always watching it and very concerned about it,” said Loren Hopkins, chief environmental science officer for the Houston Health Department. “It’s a carcinogen. It’s also a precursor to ozone formation and so understanding where we can go in and work on reducing benzene emissions is real vital information.”

Communities that face long-term exposure to benzene from the top 10 companies — whose annual averages ranged from 10 to 49 micrograms per cubic meter — could see as many as four additional cancers per 10,000 people, the group said, based on estimates from the EPA.

“The numbers are high enough to be worrisome,” said Eric Schaeffer, executive director of the group, “and (state officials) ought to turn their attention now to what can be done to bring those emissions down.”

Industry response

More Information About the study? The Environmental Integrity Project is a nonpartisan, nonprofit watchdog organization composed of former EPA enforcement attorneys, public interest lawyers, analysts, investigators, and community organizers, according to its website.

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The Environmental Integrity Project based its analysis on data collected by the EPA since the agency two years ago began requiring oil refineries to install monitors around the perimeter of plants to measure benzene levels.

If companies record an annual average of 9 micrograms per cubic meter or higher, they must do a root-cause analysis and submit a plan detailing corrective actions. Pasadena Refining — which was fined hundreds of thousands of dollars and sued for clean-air violations under its previous owner, Brazil’s Petrobras — was twice as high, according to the EIP analysis. Chevron last year bought the refinery for a discounted $350 million.

The other Houston-area refineries cited by the study were Royal Dutch Shell’s Deer Park plant and Marathon Petroleum’s Galveston Bay refining complex in Texas City.

Company representatives told the Houston Chronicle they are committed to comply with EPA rules and pointed to robust monitoring systems that help them identify sources of emissions.

Chevron, which also saw its Mississippi refinery in the top 10, said it is testing new monitoring technology at its facilities and has submitted a corrective action plan to the Texas Commission on Environmental Quality that’s underway.

“Protecting people and the environment is one of Chevron’s core values, and we strive to operate safely and responsibly,” said Chevron spokesman Braden Reddall.

As for Shell, the Anglo-Dutch energy giant said fence-line monitoring helped it identify and fix emissions issues at a storage tank. Shell Deer Park also was affected by a major chemical plant fire at neighboring ITC in March 2019. The energy industry’s top trade organization, the American Petroleum Institute, pointed to emissions from adjacent facilities as an inherent flaw in relying on fence-line monitoring data.

By the of the end of 2019, Shell spokesman Ray Fisher said, the Deer Park refinery was averaging just under 7 micrograms per cubic meter.

The Total Port Arthur Refinery, also in the top 10, issued a statement saying it “has a robust monitoring system in place to assist us in identifying the source of an emission, investigating its cause and implementing corrective actions. We are committed to comply with EPA rules. We take seriously our responsibility to reduce our environmental footprint.”

Likewise, San Antonio-based Valero Energy noted that monitoring at its Corpus Christi complex was well below 6 micrograms as of January.

Flint Hill Resource’s Corpus Christi complex also made the Top 10 list. A subsidiary of Kansas-based Koch Industries, Flint Hill called the report misleading, arguing that fence-line monitoring is designed for early detection of potential benzene releases and is not an accurate measure of overall air conditions in a community. The refinery’s air monitors show that it is well within public health standards, said spokesman Jake Reint.

“Even so, we constantly strive to minimize our emissions,” Reint added, citing changes to Flint Hill’s marine vessel-loading operations to significantly reduce benzene emissions, as well as new seals installed on floating-roof storage tanks.

Marathon Petroleum didn’t respond to a request for comment Wednesday.

Benzene effects

Benzene is a colorless, sweet-smelling chemical primarily used as feedstock to make other industrial chemicals. It is naturally found in crude oil.

It can be released from flares or as vapor from leaking production units, storage tanks or wastewater treatment units. Refineries and chemical plants are major sources in the Houston area, Hopkins said.

Long-term exposure to benzene can cause cancer. But even short-term exposure can result in developmental delays in young children and harm to the blood system.

Many of the levels observed so far, even if they don’t trigger the EPA’s action levels, exceed some national and California standards for chronic exposure, which are stronger than those in Texas.

“The general idea is that tracking benzene and bringing concentrations down when they are too high will also help to avoid other risks that are less well known,” said Schaeffer, of the Environmental Integrity Project.

There are 28 refineries in Texas reporting sampling results from more than 500 monitors, about half of them in the Houston region. As of Novemeber, TCEQ had written seven companies and requested an update on corrective action taken, according to documents provided by the agency.

TCEQ said compliance with the reporting requirements has been high, and according to an October agency presentation, the statewide trend was showing a reduction in the concentration of benzene being reported.

Andrew Keese, a spokesman with the state agency, said TCEQ is also evaluating the data on benzene levels for potential effects on human health. If the concentrations rise to a worrisome level, he said, “TCEQ will strongly consider taking further actions” including air monitoring using handheld equipment and focused investigations.

The agency opposed implementation of the requirements when they were initially proposed, saying they amounted to an unnecessary burden to the industry and to state and federal environmental officials.

In fact, state officials had said, the EPA’s own modeling that showed only one refinery would exceed the 9-micrograms concentration, based on industry-reported emissions, demonstrated there was no reason to require facilities to “incur costs that they would most likely pass on to customers.”

Which turned out to be inaccurate, especially for Texas.

Understanding where emissions can be reduced is key, said Hopkins. “It helps us and the state, even the companies, understand where high emissions are and where progress can be made.”

Bakeyah Nelson, executive director of Air Alliance Houston, part of a 2012 lawsuit to force the EPA to adopt stricter standards, said people need to be aware they are exposed to multiple pollutants every day.

“And in our area,” Nelson added, “to a much greater extent given the fact we have so many communities that live so close to these facilities and kids that go to school so close to some of these facilities.”

perla.trevizo@chron.com

jordan.blum@chron.com