CSB Wants OSHA, NFPA to Act on Gas Purging
A 4-1 vote Monday night at a public meeting of the board in Portland, Conn., adopted 18 urgent recommendations, including prohibiting the practices that resulted in the explosion at Kleen Energy's plant.
The U.S. Chemical Safety and Hazard Investigation Board adopted 18 urgent safety recommendations on a 4-1 vote Monday night at a Portland, Conn., public meeting about the Feb. 7, 2010, explosion at a Kleen Energy natural gas power plant in Middletown, Conn. The blast resulted from a "gas blow," a large amount of high-pressure natural gas used to clean the nearly completed plant's pipes on a Sunday morning, with the gas then vented from open pipes near the ground. Six workers died in the explosion. CSB and a commission formed by Connecticut Gov. Jodi Rell determined there are no regulations governing "gas purges" of this type, although they are frequently used at these plants because they already have a ready supply of natural gas available.
Leading the board's meeting was its new chairman, Dr. Rafael Moure-Eraso, Ph.D., CIH, who was confirmed by the U.S. Senate on June 23 along with a new CSB board member, Mark Griffon. Moure is a chemical engineer and was chair of the Department of Work Environment, School of Health and Environment, at the University of Massachusetts, Lowell when President Obama nominated him on March 22. Griffon was an environmental and occupational health consultant and a member of the Federal Advisory Board on Radiation and Worker Health under the Energy Employees Occupational Illness and Compensation Program Act.
CSB's Twitter site announced the adoption of the 18 recommendations and said Moure promised at the meeting to press OSHA to adopt the four recommendations directed to it:
- Prohibit the release of flammable gas to the atmosphere for the purpose of cleaning fuel gas piping
- Prohibit flammable gas venting or purging indoors. Prohibit venting or purging outdoors where fuel gas may form a flammable atmosphere in the vicinity of workers and/or ignition sources
- Prohibit any work activity in areas where the concentration of flammable gas exceeds a fixed low percentage of the lower explosive limit (LEL) determined by appropriate combustible gas monitoring
- Require that companies develop flammable gas procedures and training that involves contractors, workers, and their representatives in decision-making
CSB recommended that NFPA enact a Tentative Interim Amendment and permanent changes to the National Fuel Gas Code (NFPA 54/ANSI Z223.1) that address the safe conduct of fuel gas piping cleaning operations. At minimum, CSB said, NFPA should require inherently safer alternative cleaning, such as air blows or pigging with air to remove debris from piping -- which is an essential and mandatory step in readying a natural gas power plant for operation, CSB concedes -- and should remove the current fuel gas piping exemption in NFPA 54 for power plants and systems with an operating pressure of 125 psig or more. (The Kleen Energy gas blow was conducted at about 650 psig, so it was exempt, according to CSB investigators.)
Major manufacturers of gas turbines -- GE, Siemens, Solar, Mitsubishi Power Systems, Pratt & Whitney, and Rolls-Royce -- should give their customers "comprehensive technical guidance" on inherently safer cleaning methods and should warn against using fuel gas to clean pipes, CSB recommended.
Statements of witnesses at a June 28 U.S. House Education and Labor hearing about the Kleen Energy blast are here and here.