Although federal investigators are unsure about what caused a fatal explosion on Feb. 7 at a powerplant under construction in central Connecticut, local officials are saying the accident occurred during blowdown operations in preparation for the facility’s scheduled opening this summer.

Photo: AP/Wideworld
Combined-cycle plant, set to open later this year, suffered severe structural damage.

Reports are unconfirmed that authorities are investigating the possibility that a welder’s torch may have created the spark that caused the blast. But a spokesman for the project owner, Kleen Energy Systems LLC, Middletown, Conn., says police were still treating the site as a crime scene and that a criminal investigation is under way.

The accident occurred just three days after the U.S. Chemical Safety and Hazard Investigation Board approved safety recommendations on gas purging after a months-long investigation into a similar explosion at a ConAgra beef-jerky production facility in Garner, N.C. “We haven’t been allowed on-site yet to know one way or another [what caused the explosion],” says Daniel Horowitz, a spokesman for the safety board. “But clearly gas purging is a very serious issue for us.”

The blast at the Kleen Energy Systems plant occurred shortly after 11 a.m., causing severe structural damage to the 620-MW combined-cycle electric generating facility that was being built on a former feldspar quarry site near Hartford. The project, which began in 2007, was about 93% complete and has been undergoing testing since last summer. About 114 workers were on the site at the time of the explosion, with many still inside the building. So far, five have been confirmed dead and 12 injured, with one in critical condition, according to a spokesman for the project’s Torrington, Conn.-based contractor, O&G Industries. Search and rescue operations were ongoing at press time.

The dead workers were identified as Raymond Dobratz, 58, of Old Saybrook, Conn., a supervisor pipefitter for Keystone Construction and Maintenance Services Inc., Rowley, Mass., a project subcontractor; Ronald J. Crabb, 42 of Colchester, Conn., a pipefitter general foreman for Keystone; Peter Chepulis, 48, of Thomaston, Conn., a Keystone pipefitter; Roy Rushton, 36, of Hamilton, Ontario, a supervisor for Coverflex Manufacturing Inc., a Houston firm contracted to install insulation on two plant gas turbines; and Chris Walters, 48, of Florissant, Mo., a temporary Keystone safety engineer.

According to a Jan. 15 report filed by Kleen Energy with the Connecticut Dept. of Public Utility Control (DPUC), construction activity over the last quarter has involved pipe installation, hanging and welding throughout the site.

The amount of welding required had exhausted the supply of available union members in Connecticut, requiring O&G to bring in workers from New York and Massachusetts. At the time the report was filed, 760 workers were on-site, and the project was considered to be ahead of schedule. “We have all our technical people looking at this and trying to analyze what the implications are, both short- and long-term,” says a DPUC spokesman.

Don Holmstrom

Middletown Mayor Sebastian Giuliano said on Feb. 7 that the 800- to 1,000-ft natural-gas line that runs through the building was being purged at the time of the explosion, but the safety board cautions against linking the explosion with purging a gas line until its investigation is complete. “The [board’s] investigative team will examine the activities that were ongoing at the time of this accident, including any gas purging, as indicated by initial reports,” says lead investigator Don Holmstrom.

Earlier this month, the board approved safety recommendations in response to the North Carolina facility blast that left four dead and three critically injured. The board urged the National Fire Protection Association and the American Gas Association to enact changes to the National Fuel Gas Code, requiring purged fuel gasses to be directly vented to an outdoor location, away from workers and ignition sources.

The board’s probe of the ConAgra incident determined the explosion was caused by accumulation of significant amounts of natural gas that had been purged indoors from a new, 120-ft pipe during startup of a new water heater. Holmstrom referred to the purging of flammable gases into building interiors as a “recipe for disaster.”

Energy Investors Funds, which acquired an 80% indirect investment in the plant in 2008, declined to comment specifically on the explosion, saying only that it is cooperating with authorities.