The U.S. Chemical Safety Board (CSB) has said Mitsui & Co Ltd’s petrochemical storage operation had no alert system in place to warn of releases from tanks at the ITC Deer Park terminal in Houston that caught fire in March.
On March 17, 2019, at approximately 10:00 am, a large fire erupted at the Intercontinental Terminals Company, LLC (ITC) bulk liquid storage terminal located in Deer Park, Texas. The fire originated in the vicinity of Tank 80-8, an 80,000-barrel aboveground atmospheric storage tank that held naphtha, a flammable liquid, typically used as a feedstock or blend stock for production of gasoline.
ITC was unable to isolate or stop the release of naphtha product from the tank, and the fire continued to burn, intensify, and progressively involved additional tanks in the tank farm. The fire was extinguished on the morning of March 20, 2019.
While the exact cause of the ITC fire remains unknown, the U.S. Chemical Safety and Hazard Investigation Board (CSB) say there likely was a mechanical problem in a pump circulation system that transferred butane to a tank containing naphtha.
Tank 80-8 was an 80,000-barrel aboveground atmospheric storage tank. It was leased to another company for naphtha storage and for naphtha-butane blending operations. ITC injects butane into the naphtha product using external piping and equipment (piping manifold) to increase the octane level of the fuel product.
The control system is designed so that the butane injection operation cannot be started unless the Tank 80-8 pump is turned on to ensure that product is circulating. When this condition is met, an ITC operator can open an actuator valve by pressing the ON button at the truck loading rack to allow the butane unloading to begin.
The pump stays on throughout the unloading activity and for several hours afterward in order facilitate the mixing of naphtha and butane.
“ITC did not equip the Tank 80-8 piping manifold with emergency or remotely operated isolation valves,” said the incident report. “Such isolation valves could stop an uncontrolled release if for example, the pump or piping manifold were damaged. Instead, to isolate equipment such as the pump, ITC operators must manually close both the Tank 80-8 supply valve to the pump and the return valve from the pump back to the tank. Under a major fire scenario resulting from a leak near this equipment, neither ITC operators nor emergency responders could access the area to close these manually operated valves.”
The investigation is ongoing.
For more information visit www.csb.gov