Jun 26, 2013 11:34 Possible causes of plant explosion probed Possible causes of plant explosion probed BY DAVID J. MITCHELL| River Parishes bureau June 26, 2013 Comments GONZALES — State and federal investigators probing the cause of the deadly blast June 13 at the Williams Olefins plant plan to inspect a key element of the facility this week that one federal investigator said “failed catastrophically.” A U.S. Senate committee also scheduled a hearing for Thursday to look into the fire that killed two and injured 101. Investigators said they hoped to get a close look at a heat exchanger in the Ascension Parish facility’s propylene fractionation unit, an area company officials have already identified as being near the explosion and fire around 8:30 a.m. June 13. As of Mon day, one worker remained hospitalized at the Baton Rouge General Medical Center’s burn unit while another being treated at Our Lady of the Lake Regional Medical Center was released Thursday, a hospital spokeswomen said. The U.S. Chemical Safety Board, the U.S. Occupational Safety and Health Administration and the Louisiana State Fire Marshal’s Office are among the agencies trying to determine the cause of the fatal blast that sent a fireball a few hundred feet in the air. In the heat exchanger, hydrocarbons are mixed and heated to react chemically and then are cooled before being separated. Propane and propylene, which are both highly flammable, are involved in the processes, authorities said. Daniel Horowitz, the Chemical Safety Board’s managing director, said Friday this heat exchanger “failed catastrophically.” Don Holmstrom, the chemical board’s investigator, said officials have been working with structural engineers to evaluate overhanging hazards near the heat exchanger and develop a safety plan so investigators can get their first up-close look. The heat exchanger is also known as a reboiler or thermal conversion unit. “There is a lot of safety work that needs to be done to make it safe to go in there,” Holmstrom said. “Late next week, we hope to go in there and hope to have more information.” The Chemical Safety Board, which makes recommendations to prevent future incidents, was conducting interviews last week. The U.S. Senate Environment and Public Works Committee plans to discuss the Williams Olefins fire at a Thursday hearing. “Tragically, Louisianians’ lives were lost, and we need to figure out exactly what happened,” U.S. Sen. David Vitter, R-La., who visited the Geismar facility the day after the explosion, said in a statement. Vitter is the committee’s ranking minority member. Sen. Barbara Boxer, D-Calif., chairs the committee. “Our hearing should be educational, and it’s very important to understand where things stand in risk management as well as safety and response measures at both the state and federal level,” he said. State Fire Marshal’s Office officials have said no “suspicious circumstances” that would point to arson have been found. But Brant Thompson, deputy chief at the state office, said state fire investigators believe the epicenter of the explosion was in a cooling zone of the thermal conversion unit or heat exchanger. Thompson described the unit as two rows of horizontally stacked, elongated cylindrical vessels that look something like the backyard propane tanks sometimes seen behind homes in rural communities. He said pipes connect to the cylinders to deliver and remove products as they mix and react. “It’s essentially an elongated reaction zone,” Thompson said. He said the explosion appears to have originated from the cooling area in one of those cylinders. But Holmstrom said it is too soon to say what the physical origin of the fire was, though investigators know the general area and what equipment was involved. He said in addition to the up-close look, investigators are waiting on detailed electronic data that track the processes occurring just before the incident happened. “We hope to get some of that data this weekend and review it,” he said. Tom Droege, a Williams spokesman, said the company is cooperating with investigators. Meanwhile, class-action lawsuits filed in the 23rd Judicial District Court in Gonzales are gathering against Williams Olefins LLC. The first suit was filed June 14, a day after the explosion, by a contractor working at the nearby BASF facility. In the suit, the contractor complained of effects from the fire’s releases. Three more suits also seeking class action status had been filed against Williams as of late Friday afternoon. All three new suits include named plaintiffs working in neighboring plants, attorneys said. But one of the suits filed Friday afternoon, naming Eric Simon Sr., Javis Jackson and Travis Joseph as plaintiffs, also includes two truck drivers making deliveries to Williams at the time of the fire, plaintiffs’ attorney Tim Pujol said. Droege said company policy is to not comment on litigation.