Monday, June 7, 2010

A review of the Bhopal disaster including perspective from former Union Carbide insiders involved in revamping Carbide's process safety program from the ground up after the accident.

At approximately 1:20 p.m. on March 23, 2005, a series of explosions occurred at the BP Texas City refinery during the restarting of a hydrocarbon isomerization unit. Fifteen workers were killed and 180 others were injured. Many of the victims were in or around work trailers located near an atmospheric vent stack. The explosions occurred when a distillation tower flooded with hydrocarbons and was overpressurized, causing a geyser-like release from the vent stack.

A chain of explosions at the state-owned PEMEX Cactus natural gas plant near the town of Reforma, Chiapas, killed at least 6 workers and injured 30 on July 26, 1996. The facility is the largest natural gas plant in Mexico and one of the biggest in Latin America. The explosion flattened two plants that produce 30 percent of the country's natural gas. The Cactus plant had five serious accidents in the last 20 years, with the worst disaster in November 1984 in San Juanico that killed 410 people.

An explosion occurred at the West Pharmaceutical Services plant in Kinston, NC, USA on January 29, 2003. The facility manufactured rubber components for pharmaceutical delivery devices. The explosion occurred in the rubber compounding section of the plant, which suffered extensive damage. The explosion resulted in six fatalities and a number of injuries.

An in-depth investigation by West Pharmaceutical revealed that the explosion involved a polyethylene dust. Unlike typical dust explosion events, no residual combustible dust accumulations were found in the facility. The polyethylene dust that fueled the explosion originated from an aqueous slurry used to coat rubber strips, and not from a dry powder. The investigation revealed that combustible fugitive dust from dried slurry had accumulated above a suspended ceiling along with other non-combustible dusts. The damage from the explosion was not uniform throughout the facility; the greatest damage was well removed from the location of initiation.

At approximately 1:00 p.m. on the 23rd October 1989 Phillips’ 66 chemical complex at Pasadena, near Houston (USA) experienced a chemical release on the polyethylene plant. A flammable vapor cloud formed which subsequently ignited resulting in a massive vapor cloud explosion. Following this initial explosion there was a series of further explosions and fires.

The consequences of the explosions resulted in 23 fatalities and between 130 – 300 people were injured. Extensive damage to the plant facilities occurred.

The day before the incident scheduled maintenance work had begun to clear three of the six settling legs on a reactor. A specialist maintenance contractor was employed to carry out the work. A procedure was in place to isolate the leg to be worked on. During the clearing of No.2 settling leg part of the plug remained lodged in the pipework. A member of the team went to the control room to seek assistance. Shortly afterwards the release occurred. Approximately 2 minutes later the vapor cloud ignited.

The CSB recently released their report on the Imperial Sugar Dust Explosion and Fire where 14 were killed and 36 injured.  This session will review this case study and report.  We will focus on lessons learned as a result of the investigation and during disaster response.