A chemical leak at the Pemex Deer Park, Texas, refinery Oct. 10 killed two contract workers and resulted in dozens of injuries.
The chemicals released include hydrogen sulfide and sulfur dioxide, according to the Texas Commission on Environmental Quality (TCEQ). Hydrogen sulfide smells like rotten eggs and at low levels can cause nausea and headaches along with other minor symptoms.
Exposure at higher levels, 700 to 1,000 ppm, causes rapid unconsciousness, and death within minutes when exceeding 1,000 ppm, according to the U.S. Occupational Health and Safety Administration.
Pemex, short Mexican state-owned petroleum company Petróleos Mexicanos, issued a statement confirming the incident, including two deaths.
At 4:40 p.m. CT an acid gas leak was reported in one of the processing units of the Deer Park refinery, the company said.
The company notified authorities, shut down its coking and hydrotreatment units and began safety venting, according a news release translated from Spanish.
Another 35 workers were injured, several news outlets reported.
The Deer Park police received notification of the leak at 5:25 p.m. and issued a shelter-in-place order for residents two hours later. The department lifted the order after air-monitoring reports from county pollution control did not indicate any hazardous pollutants in the air, the Deer Park police said.
Companies must submit an initial notification in the State of Texas Environmental Electronic Reporting System within 24 hours of the event if emissions exceed the reportable amount, TCEQ said.
The U.S. Chemical Safety and Hazard Investigation Board (CSB) said Oct. 11 it’s launching an investigation into the incident.
“This is a very serious incident that caused multiple fatalities and injuries and potentially put the surrounding community at risk,” said CSB Chair Steve Owens.
Region's History of Chemical Accidents Raises Alarms
The leak is the second chemical-related accident in the region in less than a month.
On Sept. 16, a vehicle crashed through the gate of an Energy Transfer liquified natural gas pipeline in nearby La Porte, Texas, causing a fire that burned for several days.
The Deer Park site shared by Pemex and Shell has been the site of past safety incidents. The refinery was a 50-50 joint venture between Shell and Pemex. Shell sold its remaining shares to Pemex in 2021 but maintains chemical operations at the site adjacent to the Pemex refinery.
In 2023, Texas filed a civil lawsuit against Shell related to a chemical fire that burned for three days at the site. The state is seeking more than $1 million, according to an Associated Press report. The Texas attorney general’s office claimed the May 5, 2023, fire resulted in air and water contamination violations.
Luke Metzger, executive director of Environment Texas, said the facility has a long track record of accidents and pollution violations.
Environment Texas and the Sierra Club sued Royal Dutch Shell and two of its affiliates in January 2008 over claims of air pollution at the Deer Park refinery. Shell settled the suit for $5.8 million.
Metzger said chemical companies in the region do not have much motivation to change. TCEQ, the state’s environmental agency has issued fines for about 10% of clean-air law violations annually, he said. Also, when penalties are imposed, they tend to be minimal, he added.
“We think that sends a message to the industry that it’s often cheaper to just pay a fine than to invest in prevention,” he said.
When reached for comment, a TCEQ spokesperson replied that its enforcement statistics are available online in its annual enforcement report. TCEQ receives about 10,000 complaints each year related to environmental concerns, according to the report.
The agency has the authority to issue penalties up to $25,000 to $40,000 per day depending on the type of violation.
