Two scientists were changing hydrogen gas cylinders in an analytical laboratory. They were in the process of removing the cylinder cap from the new cylinder when a loud hissing noise occurred and they quickly realized that the tank was leaking. After making a quick attempt to shut off the tank, which was not possible, they left the lab and notified their supervisor.

After checking that everyone was out of the lab, the supervisor paged all staff in the vicinity to immediately evacuate to the staging area. Facility management and ES&H management were notified about the situation, and they contacted the local fire department to respond to the site in case the venting gas was ignited.

The first responders arrived quickly and spoke with facility management and the site view more

Facility management confirmed that a hydrogen gas cylinder did not comply with the limiting condition for operation (LCO) for flammable gas control systems in the lab's safety requirements. Earlier erroneous calculations had shown that a release of the entire contents of the cylinder into the hood could not reach the lower flammability limit (LFL).

The facility manager determined that the LCO was applicable and immediately entered the action statement in the safety system, which required immediate termination of normal operations in the affected wing of the building. Because normal operations had already been terminated in the wing for HVAC maintenance, further efforts to terminate normal operations were not necessary. The hydrogen cylinder was removed from the hood, thus view more