Investigation launched into fatal hydrogen sulfide leak that killed two US workers

Article by Adam Duckett

Rodrigo Molina / Shutterstock.com

Pemex has been criticised for poor communication during the incident, which “left the community worrying whether they were safe”

THE US Chemical Safety and Hazard Investigation Board (CSB) has launched an investigation into a hydrogen sulfide leak at a Texas refinery that killed two workers and injured more than a dozen others.

The leak occurred at Pemex’s refinery in Deer Park, Texas on 10 October. Two contractors died and 35 others were affected, with 13 taken to hospital for treatment. Around 20 t of toxic hydrogen sulfide leaked over the course of 7 hours 40 minutes according to documents filed to regulators seen by Reuters.

Pemex said workers were conducting maintenance activities on the refinery’s amine regeneration unit when the leak occurred.

Pemex said: “In order to mitigate the impact, the operation of the coking unit and hydrotreatment units was proactively stopped, and safety venting was carried out.”

As a result of the leak, a section of the local highway was temporarily closed and residents in two neighboring cities – Deer Park and Pasadena – were ordered to stay in their homes, close windows, and shut off air conditioners.

CSB chairperson Steve Owens said: “This is a very serious incident that caused multiple fatalities and injuries and potentially put the surrounding community at risk.”

Lawsuits have been filed by the family of one of the workers killed in the incident and by workers alleging they have suffered neurological disorders and respiratory problems.

A local official, commissioner Adrian Garcia, has admonished Pemex for poor communication during the incident. He said the company failed to provide a spokesperson in the early stages of the incident and didn’t pass on air quality information from monitors within the refinery. This lack of information “left the community worrying whether they were safe,” Garcia said.

The refinery, which has a processing capacity of 312,500 bbl/d, was previously operated as a joint venture with Shell but Pemex bought its partner out in 2021 in a deal worth US$596m.