An explosion occurred within the hydrogen processing system of a chemical plant that produces sodium chlorate for bleaching pulp and paper. The chemical process utilizes electrolytic cells and is pH-dependent. Hydrogen is produced as a byproduct and is utilized as a fuel.

At the time of the incident, the plant was at an abnormal operating level of 25% capacity. A non-routine maintenance operation to repair high-pH liquid piping was in progress. To assist, operations personnel rerouted the high-pH liquid stream to the plant sump. However, in doing this, the liquid eventually made its way back into the electrolytic process by design. Ultimately this created the root cause of the explosive condition in that the pH of the electrolytic process increased faster than the computer- 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