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I work in the industry and am keeping tabs on it. Just thought I would post this for those who care.

Statement of Bill Hoyle
Investigation Manager
U.S. Chemical Safety and Hazard Investigation Board Texas City April 7, 2005

CSB arrived at the BP America Texas City refinery on March 24, and we have had investigators at the site each day since. The Chemical Safety Board currently has a field team of 13 investigators here at the BP refinery. We are conducting a full root-cause investigation of the accident, and in due course our Board will be issuing safety recommendations designed to prevent similar accidents in the future.

The CSB team has conducted 75 detailed interviews with eyewitnesses, including BP management and hourly employees and contractor staff.

These interviews have provided an increasingly clear picture of the events of March 23.

The accident occurred during the restarting of process equipment known as the raffinate splitter, which separates hydrocarbons including pentane and hexane. We believe that the raffinate splitter developed excess internal pressure, causing one or more pressure relief devices to open. When these devices opened, hydrocarbon liquid and vapor flowed into a vessel known as a blowdown drum. The blowdown drum includes a 100-foot-tall vent stack which goes to the atmosphere.

The blowdown drum was not able to contain the hydrocarbon release, and it was not connected to a flare system to combust the flammable vapor.

Instead, there was what witnesses describe as a geyser-like release of hydrocarbon liquid and vapor directly from the stack. The witnesses saw the liquid and vapor fall to the ground. Shortly afterward, the hydrocarbon ignited, and within seconds there was a powerful explosion, which resulted in deaths and injuries among personnel in nearby trailers and elsewhere.

The exact ignition source for the hydrocarbon remains unknown, as does the cause of the excess pressure in the raffinate splitter. When our team entered the explosion site last Friday, we found the remnants of about 30 vehicles in close proximity to the vent stack, including some within 25 yards. However, further examinations will be performed, and there are multiple possible ignition sources.

Six CSB investigators wearing respirators entered the area in and around the isomerization unit yesterday for about four hours. They continued the work of examining and documenting the site, through photographs, measurements, and notes. Now I will discuss our planned activities for the next several days

The site remains hazardous due to overhanging metal debris. There are also hazardous chemicals that remain trapped inside damaged process equipment. We have developed a joint plan with OSHA and BP for rendering the site more safe. The process equipment will be depressured, hanging debris will be removed, and a satellite control room will be made safe for entry. We have also concluded an agreement for the secure storage of physical evidence, and we are developing a plan for sampling chemicals that remain in the unit.

Our team has continued identifying blast markers in the affected area.
Measuring the blast damage will assist us in reconstructing the size, nature, and origin of the explosion. We are also delineating how far flammable vapors traveled through the area before the explosion.

The isomerization unit control room housed important computer records of the operating conditions in the isomerization unit prior to the blast.

We are currently working with Honeywell, the manufacturer of the computer control system, to recover and decipher those computer records.

As you can see, the investigation has been proceeding on multiple fronts, and we expect the field phase of our investigation to continue for at least several more weeks.

Today we are providing reporters with about two dozen photographs our investigators have taken in and around the isomerization unit in recent days. The photographs show the overall condition of the unit, the position of the atmospheric vent stack, and the heavy blast damage to nearby trailers and vehicles.