On Sunday morning, a massive explosion rocked the Kleen Energy gas power plant in Middletown, Conn. At least five workers died in the blast, which shook houses up to 10 miles away. Rescuers continue to sift through rubble in search of survivors. Dozens of people may still be trapped by debris.
Workers were trying to purge gas lines when the explosion happened, according to Middletown’s deputy fire marshall. At press conference last night, Middletown Mayor Sebastian Giuliano blamed the blast on the gas purging.
Just three days before the accident, the U.S. Chemical Safety Board, an independent federal agency charged with investigating serious chemical accidents, held a public meeting to issue urgent recommendations about gas purging safety. According to the report:
The use of gas-fired equipment is ubiquitous in general industry, creating a potential for widespread hazards if purging of gas lines is not conducted in the safest possible manner; several serious explosions have occurred in the past four years.
When installing a new natural gas line, the air in the line must be displaced before the gas can start flowing. The trick is to stop pumping the gas when all the air has been expelled. Otherwise, the flammable fumes can accumulate in the air and explode; lethal levels can build up before anyone smells gas. When gas levels rise above the gas’ lower explosive threshold, any source of ignition, from a cigarette to a piece of electronic equipment, can set off the gas. The Wall Street Journal is reporting rumors that a propane heater was somehow implicated in the disaster.
The urgent CSB recommandations were issued after four workers were killed last June during an attempted purge of a natural gas line at the ConAgra Slim Jim plant in Garner, North Carolina. The explosion brought down nearly 40% of the roof of the 87,000-sq-ft packaging and wareouse facility. Hundreds of workers were laid off until further notice.
The CSB report cited six other major purging accidents in five states since 1997. One such explosion injured 14 workers and damged three floors of a 30-story Hilton Hotel in California in 2008. A purging accident at a Ford Rouge plant in Dearborn, Mich., killed six workers and caused a billion dollars in damage in 1999.
The CSB recommended tougher new rules for installing natural gas facilities. Whenever practicable, gas should be vented outdoors and away from buildings, not into rooms. If it’s not possible to vent outdoors, all non-essential personnel should be evacuated while the lines are being purged. Employees should be taught to rely on combustible gas detectors, and not smell, to monitor gas levels.
It is not clear how the gas was being purged at the Middletown plant. However, given that between 100 and 200 people were on the jobsite yesterday, it seems unlikely that non-essential personnel were evacuated before the purge.
The Kleen Energy blast is still being investigated. The CSB has sent a seven-member team of experts to Middletown to help; they’re expected to arrive onsite later today.