About 75,000 cubic feet of highly flammable vapor caught fire last month at an Ascension Parish renewable fuels plant as crews were working on equipment that uses hydrogen to treat animal fats and other sources of biofuel, according to reports that were recently made public.Â
Crews were working on a membrane that purifies hydrogen when the release happened about 8:30 a.m. Sept. 19 at Chevron's Renewable Energy Group complex in Geismar, company officials told state regulators. Two workers were burned and taken to Baton Rouge General Hospital, hospital officials said. One was released the day after the incident and another a week later.
"They have both been released and (are) doing well," hospital officials said Thursday.Â
New information on the fire
Public follow-up reports filed with the state Department of Environmental Quality reveal new details about the fire and what kind of emissions it generated.
In addition to the volumes of hydrogen that were combusted, the incident also released 48,000 cubic feet of hydrogen and flammable fuel gas into the air without being burned.
The fire, which led to a shelter in place order, sent materials off the plant's site, releasing small amounts of carbon monoxide, nitrogen oxides and fine particulates. It also released 590 pounds of volatile organic compounds and 689 pounds of ionized ammonia, also known as ammonium.
All are commonly produced when things burn.
The lightest and smallest element on the periodic table, hydrogen is an extremely flammable gas that can easily ignite at low concentrations and, according to gency, has a potential to leak due to its tiny size. The volume that caught fire at REG probably weighed around 420 pounds but could fill about 85% of an Olympic-size swimming pool.
Industry and EPA guides say an important way to deal with a hydrogen fire is to cut off the source and then purge the remaining gas from burning equipment.
DEQ reports show firefighters depressurized the plant equipment and then purged it with inert nitrogen gas. The fire was out in just less than an hour.
The state environmental and federal workplace safety regulators say they still have the fire under investigation, and Chevron REG officials say they are working closely with those agencies.
"At this time, we are still in the process of investigating the incident," company officials said in a statement last week.
The plant's history
In the mid-2010s, the REG plant operating before Chevron took over in 2022 had two fires that led to workers being burned, including one involving a hydrogen leak during repairs, according to a .
In Chevron REG's more recent history, the complex hasn't had major air releases or fires.
It did have an unusual flaring event in January 2021 that caught the attention of neighboring facilities. An equipment failure led to liquid hydrocarbons being improperly routed to a flare designed for vapors, causing flames and soot that were initially reported by bystanders as a fire, a says.
In operation , the Chevron REG complex is considered a minor source and has located itself on a next-door plant's property for access to feedstocks from neighboring facilities, including hydrogen, avoiding the need to produce them itself.Â
The company uses proprietary catalysts and hydrogen to treat waste biofuel sources, such as beef tallow and other animal fats, vegetable oils and used cooking oil, to break down more complex fatty molecules known as triglycerides. The process turns the animal and vegetable fats into chemicals closer to more traditional hydrocarbon fuels, like diesel, according to Ìý»å´Ç³¦³Ü³¾±ð²Ô³Ù²õÌý²¹²Ô»å .
The Geismar plant also can burn hydrogen for fuel.