On April 3, 2023, at approximately 1:45 p.m., flammable vapor within a storage tank ignited, resulting in an explosion and a major fire at a Tank Terminal in Louisiana. The incident seriously injured two contractors and caused over $15 million in property damage.
The company provides storage tanks for customers to store liquids in large quantities. The company's investigation found that before the incident, one of the company’s 8.4-million-gallon storage tanks (“tank”) contained natural gas condensate that was drained from the tank in 2021. After removing the flammable liquid, the tank’s manways were opened for several weeks for maintenance work inside the tank.
On August 29, 2021, Hurricane Ida made landfall south of the facility as a Category 4 hurricane with maximum sustained winds of 150 miles per hour. After the hurricane, the company discovered that a hatch covering the opening for the ladder to access the tanks’ internal floating roof had broken off.
In 2023, the company hired a contractor to weld a new hatch cover onto the tank. As two contractor employees were working on top of the tank, flammable vapor inside the tank exploded, seriously injuring both workers. The two contractor workers were transported by helicopter and admitted to a hospital for treatment of their severe burn injuries while other emergency responders fought the resulting tank fire
Flammable hydrocarbon liquid burned in the tank for about nine hours before emergency responders extinguished the fire.
The company's investigation revealed that the company issued a hot work permit for the grinding and welding to install the new hatch cover. Air monitoring conducted around the access ladder opening and up to two feet inside the tank’s opening showed no flammable vapors. The company issued a work permit that required the contractor workers to cover the opening with a fire blanket and to perform continuous air monitoring on the tank’s roof.
Before issuing these permits, workers reviewed the facility’s storage tank inventory records, which indicated that the tank was empty. However, the tank’s piping was not locked out, and no manways were opened to confirm that the tank contained no residual flammable liquid. As a result of the incident, the company created a tank database showing the operational state of each tank, identifying whether the tank is in service, cleaned, degassed, or gas-free.
Probable Cause
Based on company's investigation, the CSB determined that the probable cause of the incident was the presence of flammable hydrocarbon vapors inside the tank while hot work (grinding or welding) was being performed on the tank’s roof. Not thoroughly draining, cleaning, and purging the tanks to remove the flammable material before starting the hot work contributed to the incident. Additionally, ineffective air monitoring practices to identify the presence of flammable hydrocarbon vapor contributed to the incident.
Source:CSB.gov
No comments:
Post a Comment