Explosion in chemical plant

At an agrochemical plant, an explosion occurred near a drained hydrofluoric acid tank, when 4 employees were welding on adjacent pipelines.
An investigation was launched to determine this accident’s causes. The presence of hydrogen might have been the source.

INTIATING CAUSE may have been he presence of hydrogen in the drained acid tank.
On the ROOT CAUSE can only be speculated.

unknown

DESCRIPTION OF THE PROCESS
Hydrochloric acid is non-oxidising but very corrosive acids and is handled in dilute solutions. Contact with metals produces hydrogen gas, which xan ignite and explode. It produces poisonous gas, including chlorine, in a fire.

However, in this case, the presence of hydrogen as reason for the exposion is only given as a possiblity.

one fatality and three injuries fro mthe explosion.
air pollution measurements recorded around the plant did not indicate the presence of any toxic products, impact on both the environment and local residents would be minimal.
Except for the unit already shut down for maintenance, plant activity was not interrupted.

The company fire brigade extinguished the fire.