DEER PARK, Texas — A newly released report revealed the cause of last month's deadly chemical release in Deer Park.
The U.S. Chemical Safety Board report showed what happened the day two workers died and more than a dozen others were injured.
The incident happened on Oct. 10 around 4:20 p.m. at the PEMEX facility off Highway 225.
According to the report, two contract workers opened a flange on a piping segment containing hydrogen sulfide gas but the work was supposed to be done on a different piping segment about five feet away.
One of those contract workers died. Another contract worker from a different company who was working about 250 feet away from the release also died.
"Hydrogen sulfide is a highly toxic substance that can result in serious injury and death even at low concentrations. This dangerous incident resulted in the death of two workers and put other workers and the surrounding communities at very serious risk," CSB Chairperson Steve Owens said.
The release caused a shelter-in-place order to be issued for several hours that day. It also forced Highway 225 to be closed in both directions near Beltway 8 for several hours.
What is hydrogen sulfide?
Hydrogen sulfide is a flammable, colorless gas that smells like rotten eggs, according to the Agency for Toxic Substances and Disease Registry. It occurs naturally in crude petroleum, natural gas, volcanic gasses and hot springs. It can also result from bacterial breakdown of organic matter.
It's also created in your mouth and digestive tract during the digestion of food containing vegetable or animal proteins.
It's primarily used during the production of sulfur and sulfuric acid.
How can it affect your health?
The respiratory tract and nervous system are the most sensitive targets of hydrogen sulfide toxicity.
Exposure to low concentrations can irritate the eyes, nose or throat. It can also cause breathing issues for people with asthma. It can cause headaches, poor memory, tiredness and balance problems.
Exposure to high concentrations can cause loss of consciousness, and in some cases, respiratory distress or arrest.