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

Incident Synopsis
While transferring liquid H2 from a tanker, the burst disk ruptured at 50 psi. The pressure limit for the operation was 30 psi.

Cause
The operator turned on the pressure valve and left it unattended, permitting pressure buildup past the allowed 30 psi.

Incident Synopsis
While disconnecting a liquid H2 fill line from a liquid H2 trailer, liquid H2 escaped, burning a second man who was holding the hose. The man was burned on his hands and on his stomach.

Cause
The liquid H2 shut off valve was partially open, but both men assumed it was closed. Prescribed clothing was being worn.