“Our thoughts and prayers go out to the families, friends and loved ones of those workers killed and injured in Sunday’s explosion in Middletown,” said Labor Secretary Hilda Solis, in a press statement issued in the aftermath of Sunday’s explosion at the Kleen Energy Plant in Middletown, Connecticut that left five workers dead and at least 12 injured. “The safety and health of workers is of paramount importance to me and to the U.S. Department of Labor. Inspectors from OSHA arrived on site Sunday afternoon to conduct a comprehensive investigation and are working in cooperation with other agencies.”

According to press reports, workers were purging the pipelines of natural gas, the main source of fuel for the plant, in preparation for the central Connecticut facility to open this year when the explosion occurred.

Authorities said Monday that they had accounted for everyone working at the plant at the time of the explosion, but were not certain all the dead and injured had been found, according to press reports.

In a post on the Internet forum EHSQ Elite, one health and safety operations manager said, “Adverse weather can play havoc in these conditions. At this stage rescue, recovery, treatment, counseling and communication are the key.”

U.S. Chemical Safety Board investigator Don Holmstrom said in a press statement the CSB had issued urgent safety recommendations just last Thursday related to purging, the clearing of air during maintenance or installation of new piping. The board’s recommendations resulted from the CSB’s ongoing federal investigation into the June 9, 2009, natural gas explosion at the ConAgra Slim Jim production facility in Garner, North Carolina, which caused four deaths, three critical life-threatening burn injuries, and other injuries that sent a total of 67 people to the hospital.

The CSB issued a safety bulletin on gas purging in October 2009, due to the occurrence of multiple serious accidents during purging operations. Key safety lessons: purging gases to a safe location outdoors away from ignition sources, evacuating non-essential workers during purging, using combustible gas monitors to detect any hazardous gas accumulations, and effective training for personnel involved in purging,