Cleaning With Gas Is Common, Lethal

A study by the Chemical Safety & Hazard Investigation Board (CSB) finds that using natural gas to clean piping is a common, as well as deadly, practice and the cause of a Feb. 7 accident that killed six workers at a Connecticut power plant construction site (C&EN, Feb. 15, page 38). The Kleen Energy Systems natural gas power plant was nearing completion when natural gas caught fire and exploded while being used during a “gas blow” to remove construction debris from piping, the board notes. The plant is a combined-cycle facility that burns natural gas to turn turbines and generate electricity but then captures and uses residual heat to generate additional electricity through steam turbines. A CSB survey of the combined-cycle gas power industry finds that 63% of companies used natural gas to blow out piping, and 37% said it was their most common practice to clean pipes. Other companies used nitrogen or air. CSB Chairman John Bresland notes that more than 120 new gas power plants are in planning during the next five years and this practice needs to change.