The US Chemical Safety and Hazard Investigation Board (the Chemical Safety Board, or CSB) is an independent federal agency charged with investigating and determining the cause or probable cause of industrial chemical incidents resulting from the accidental release of a regulated or extremely hazardous substance into the ambient air. The CSB confirmed the following details related to the August 27th incident:

• Bio-Lab is a manufacturer of pool and spa treatment products. Chlorine gas is used in the production of these products and the products also contain chlorine.

• Chlorine gas, which is used in their process, is supplied from a nearby facility.

• On Monday, August 24, the night shift commenced the shutdown procedure for the facility due to the expected arrival of Hurricane Laura.

• The shutdown procedure was completed on Tuesday, August 25.

• A “ride-out” crew consisting of nine employees was assigned to the facility for the storm.

• At approximately 10:00 a.m. on Wednesday, August 26, after Hurricane Laura reached a Category 4 status, the ride-out crew evacuated the facility at the direction of the company.

• On Thursday, August 27, the rideout crew returned to the facility and discovered the fire at approximately 7:48 a.m.

• The chemical trichloroisocyanuric acid (tri-chlor) is produced and stored at the facility.

• The company reported the amount of tri-chlor stored at the facility on August 25, 2020, was approximately 835 tons.

• The company reported that a significant section of the roof of the warehouse, located adjacent to a location known as Plant 4, was damaged during the hurricane.