Flare System Pilot Ignition and Piping Fire at LyondellBasell Bayport Choate
Pasadena, TX
Incident Summary
On Thursday evening, March 12, 2026, at approximately 7:45 p.m., an operational upset occurred at the LyondellBasell Bayport Choate chemical facility. This upset triggered the plant’s emergency relief system, opening valves to vent pressure from process tanks and columns into the continuous flare system. During this relief event, a fire occurred in the piping near the flare system.
The fire burned for several hours, consuming more than 20,000 pounds of flammable gases, including approximately 15,000 pounds of n-butane, as well as isobutane and carbon monoxide. While flames were visible from as far as 45 miles away in Galveston, officials reported no injuries. Seven air monitoring stations were deployed around the facility perimeter; Harris County Pollution Control reported that no actionable levels of hazardous chemicals were detected off-site.
Facility and Industry Description
The Bayport Choate facility, located in Pasadena, Texas, is a petrochemical manufacturing site that began operations in 1969. It is recognized as the world's largest facility for the production of Propylene Oxide (PO) and Tertiary Butyl Alcohol (TBA) by volume.
The complex includes multiple units, such as the RTBE unit (added in 2022), which produces ethyl tertiary-butyl ether. The facility's primary products—including propylene glycol, propylene glycol ethers, and high-purity isobutylene—serve as essential feedstocks for the manufacturing of automotive parts, antifreeze, paints, coatings, and home furnishings.
Technical Speculation and Inferences
While a formal root cause investigation is ongoing, the following points describe potential factors based on the reported sequence of events:
Ignition Source: The Harris County Fire Marshal’s Office stated that the released flammable product was ignited by the flare's pilot light. This suggests the release occurred in close proximity to the flare tip or that a vapor cloud traveled back to the pilot from a breach in the piping.
Piping Fire Cause: The company reported a "piping fire" rather than just a standard flare combustion. This may indicate a mechanical failure of the relief header itself, such as a gasket failure or a pipe rupture due to the sudden thermal or pressure stress of the 20,000-pound relief event.
Liquid Carryover: If the process upset involved a liquid overfill that overwhelmed the flare knockout drum, liquid hydrocarbons could have entered the flare header. If this liquid reached the flare tip, it could result in "burning rain" or internal combustion within the header if air was present.
Relevant Industry Standard: API 521
API Standard 521 (Pressure-relieving and Depressuring Systems) is the primary industry guideline for managing these hazards.
Flare Header Design: API 521 provides methods for sizing relief headers to ensure they can handle the simultaneous relief of multiple units (like the 20,000 lbs reported here) without creating excessive backpressure that could cause a piping failure or prevent relief valves from functioning.
Knockout Drum Sizing: This standard defines the requirements for knockout drums, which are designed to separate liquids from gas streams before they reach the flare. Proper adherence to API 521 minimizes the risk of liquid carryover, which is a common cause of unexpected fires near the flare tip.
Flame Radiation and Location: API 521 assists in calculating safe distances between flare pilots and other equipment to prevent the ignition of accidental leaks from nearby piping.
Top Three Information Sources
LyondellBasell Bayport Choate Fact Sheet: Facility production data and history.
KHOU/OnScene.TV (March 12-13, 2026): Details on emergency response and the 9:00 p.m. incident timeline.
Harris County Fire Marshal / La Porte OEM Official Statements: Confirmation of chemical volumes (15,000 lbs n-butane) and the ignition source.