Two contracted employees were killed, and 35 were injured in the disaster.
Now, some of those injured workers are filing lawsuits.
One lawsuit, filed by three injured workers, accuses the company of hurting not just workers but also the general public.
Their attorney said the workers are still out of work.
"Dizziness, headaches, vomiting, nausea, one of them still can't get out of bed," Mo Aziz, with Abraham, Watkins, Nichols, Agosto, Aziz & Stogner, said. "What we do know is that there was an acute exposure. They were exposed to a high volume of gas in a very short time frame before they were evacuated."
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Hydrogen sulfide is a toxic byproduct of the refining process.
"The permitting process requires that hazardous materials either be eliminated from the system or be confined," Aziz said. "Here, we know that there was a loss of containment that went on for a prolonged period of time. The report that they have submitted with the EPA shows the release went on for more than 12 hours."
The lawsuit accuses PEMEX of gross negligence and malice, claiming company officials sent workers into an area with an unreasonable risk without warning them.
"In Houston, almost every month, there's a fire at a chemical plant, there's a release, or there's an explosion," Aziz said. "Every time there's an event, it's due to lack of following procedure."
Eyewitness News reached out to the refinery and the company that owns it but has yet to receive a response.
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