It was supposed to be a routine job. An LPG storage tank had been taken out of service, emptied and depressurized for internal inspection. Then the readings came back. Low levels of hazardous material were present in the vapor and dust inside the tank.
Bulk storage and transfer equipment is easy to take for granted until it fails. A stuck valve, a worn pump, or an emergency shutdown system that doesn't respond can stop transfers, create a safety risk, and cost revenue.