On October 10, 2024, at about 4:23 p.m., Repcon contractors at PEMEX Deer Park opened the wrong flange in the amine area. About five feet from the cleared line. Roughly 27,000 pounds of hydrogen sulfide came out. One Repcon worker died at the flange. An ISC contractor downwind died too. Thirteen more contractors went for evaluation. Deer Park and Pasadena sheltered in place. CSB published the final report in February 2026.
Use the five questions on this event before you write the lesson.
1. What do I know for sure right now, and what am I guessing?
What you know is what you proved on this flange, this minute: tags you can see, isolation you walked, energy state you verified. A drawing is a guess. CSB found drawings and lists were not enough to identify the right equipment. A permit that covers several jobs is not proof you are on the empty pipe.
2. Who here sees something I don’t?
Repcon was on the flange. ISC was downwind on another task and did not know a release was coming. Code Red covered monitoring. Owner ops owned the live amine unit next door. Ask who sees the live neighbor. If you do not ask, the downwind seat stays a guess.
3. Does everyone actually understand the risk, or are we just assuming they do?
CSB found workers moved from a shutdown unit into a partly live unit with H2S, still thinking they were in a shutdown. A nod is not understanding. Say it out loud: which flange, which unit is live, what is in the pipe, who is downwind, what stop means.
4. Am I doing this right, or just doing it fast?
Right is positive ID, hold points, and operator presence before you open H2S piping. Fast is treating two look-alike flanges as close enough. CSB found stop-work and operator-presence expectations were overlooked. Name the trade before the wrench turns.
5. What’s different here from what the procedure assumes?
The procedure assumed the cleared ARU6 segment. The field had an identical live ARU7 flange about five feet away. Tag out of view. Say the difference out loud. If you cannot prove you are on the empty flange, you stop.
If any answer is a guess, you stop. Name the gap. That is the work.