Valero benzene reporting scrutinized
Inspector general says EPA allows ‘masking’ technique
The Environmental Protection Agency was taken to task this month by its inspector general for allowing Valero Energy Corp. and other refiners to use a reporting technique that could be masking the levels of a cancer-causing chemical their plants are emitting.
In a September report, the federal agency’s oversight arm said the companies have been using modeling techniques in lieu of actual monitoring, allowing them to report benzene emissions at much lower than actual levels.
The could mean the San Antonio refiner’s reports could be understating how much of the carcinogen is being emitted from its plants in Texas.
In a statement, Valero said its site monitoring plans have all been approved by the EPA and that it uses air monitoring systems that exceed requirements.
The inspector general’s report — which calls on EPA to beef up oversight to ensure refineries comply with regulations for monitoring benzene — questions the agency’s decision to allow the use of modeling to estimate contributions from socalled near-field sources that would increase the total measurement for a refinery. The higher the level of emissions attributed to such sources, the lower the level attributed to that refinery.
The report notes that during one two-week sampling period, the Valero Corpus Christi East refinery measured level of 385 micrograms was about 42 times the limit, but when that measurement was adjusted to account for outside sources of benzene, it fell to 3 micrograms, or one-third of the so-called action level necessary for protecting human health.
The inspector general reviewed 13 Epa-approved site monitoring plans that rely on modeling to determine the amount of benzene they can subtract to determine final re
sults. It found five Valero plants relied solely on modeling, though Corpus Christi East was the only one mentioned by name.
Refineries that rely solely on modeling, the EPA inspector general wrote, “do not adhere to the regulations.” Such models can overestimate benzene emissions from near-field sources, thereby masking “a true exceedance of the action level” and making it difficult for authorities to know whether the refinery warrants corrective action or penalties.
‘Dubious’
“It’s dubious,” said Eric Schaeffer, executive director of the Environmental Integrity Project, a nonprofit watchdog group. “A buzzer should sound somewhere in EPA, and someone should say, ‘Wait, what?’”
The EPA considers 9 micrograms per cubic meter safe to breathe. If a company exceeds that rate, it’s supposed to investigate and correct the cause.
Benzene, though harmful, is common in the air at low levels. It’s often used to make other chemicals and is in cigarette smoke. But the adjustment by Valero cited by the inspector general should be cause for action, Schaeffer said.
“Even if there’s legitimately a strong argument it came from outside the facility, (that level) should prompt curiosity and some kind of investigation,” he said.
The inspector general said that when it reviewed the Epa approved site monitoring plans for the three refineries that made the biggest adjustments to their reported benzene levels to account for contributions from near-field sources, they were all operated by Valero. As a result, the inspector general’s office reviewed all the site monitoring plans — five, in all — for refineries owned by Valero, and found that all relied solely on modeling to estimate contributions from near-field sources.
In its statement, Valero said the protocols it employs are the same ones that the federal agency requires companies to use when getting permits.
“EPA revisits these plans, ensuring their accuracy, and that they provide the public with clarity about what emissions are actually originating from the refinery operations,” Valero wrote. “In addition, we have advanced air monitoring systems that go beyond permit compliance to identify and reduce air emissions.”
Benzene reporting
Petroleum refineries have had to measure and report benzene levels since 2015. The chemical can be emitted from a refinery’s storage tanks, wastewater or equipment. It’s a component of crude oil and can cause cancer after repeated exposure, among other health effects.
The Agency for Toxic Substances and Disease Registry, in accordance with EPA guidelines, established 29 micrograms per cubic meter as “an acute inhalation minimal risk level of benzene.” The inspector general’s report shows that from January 2018 to September 2021, Valero’s Corpus Christi East and Corpus Christi West refineries exceeded that minimum risk level at least once after they had exceeded the action level of 9 micrograms per cubic meter.
Corpus Christi leaders with the Coastal Bend Air Quality Partnership say industry and the community have worked over the past 20 years to reduce emissions. They’ve seen improvements and have monitoring devices around the city and industrial corridor, Executive Director Sharon Bailey Murphy said.
“The Coastal Bend Air Quality Partnership with active participation from local industry are committed to continue to work on ways to voluntarily reduce emissions that goes above and beyond compliance,” she said in a statement. “We still have work to do, but our continued collaboration has helped keep Corpus Christi’s air quality good.”
Schaeffer, who was previously the director of civil enforcement at the EPA, said benzene emissions remain too high nationwide year after year and that the EPA needs to start issuing deadlines to clean it up. When it comes to plants like Valero’s that rely on modeling to adjust for outside benzene sources, Schaeffer said the EPA needs to require follow-up monitoring to validate the models are correct.
Next steps
That’s a likely next step, according to the inspector general’s recommendations.
The actual tool used to measure benzene in the air is inexpensive and easy to set up, Schaffer said. A tubular filter, a little bigger than a pencil, captures benzene in the air as it flows through over two weeks. That is sent to a lab, which weighs the filter to extrapolate pollution levels during that time.
The Office of Air and Radiation responded to the report’s preliminary findings with a letter stating it would identify all plants relying solely on modeling and amend site monitoring plans to include using more devices to better account for nearfield sources of benzene.
“We believe three months is an appropriate period of time to allow for development of revised plans, and an additional three months following is an appropriate timeframe for EPA’S review and approval of the plan,” the office wrote in a letter dated June 8.
That means Valero could be required to adjust how it tracks benzene at its refineries by mid-2024.