The incident occurred in the catalytic hydrotreatment plant of an oil refinery. The plant, which began operations in September 1997, has a capacity of 1650 tons/day of light fuel oil and 1450 tons/day of heavy fuel oil. The plant was designed to desulfurize the light and heavy fuel oil fractions produced in the refinery by treating them with high-pressure hydrogen over a catalyst to remove sulfur (producing hydrogen sulfide as a byproduct). The plant has two heating/reaction/fractionating sections to treat the two fuel oil fractions, but a single gas purification and compression section for the recycled hydrogen gas.

The heavy fuel oil reactor feedstock from the vacuum distillation plant is sent to the heavy fuel oil treatment section through three pipelines equipped with flow view more

Summary
A faulty modification to a multiple-gas piping manifold allowed mixing of hydrogen and oxygen that resulted in a storage tube explosion. Several employees suffered severe burn injuries from the incident.

Incident Synopsis
An employee, without authorization, fabricated and installed an adapter to connect a hydrogen tube trailer manifold to an oxygen tube trailer manifold at a facility for filling compressed-gas cylinders for a variety of gases, including hydrogen, oxygen, nitrogen, and helium. A subsequent improper purging procedure allowed oxygen gas to flow into a partially filled hydrogen tube on a hydrogen tube trailer. An ignition occurred in the manifold piping system and a combustion front traveled into the hydrogen tube where, after traveling about a view more