Holmstrom described a gas blow as a common industry practice that entails releasing gas at high velocity through open pipe ends to remove debris from the pipes. In the Kleen Energy Plant incident, the gas built up in a congested area and was ignited by an undetermined source. Six workers died in the explosion.
“Initial calculations by CSB investigators reveal that approximately 400,000 standard cubic feet of gas were released to the atmosphere near the building in the final 10 minutes before the blast,” Holmstrom said.
“That is enough natural gas to fill the entire volume of a pro-basketball arena with an explosive natural gas-air mixture, from the floor to the ceiling,” he added.
A team of 10 CSB investigators arrived at the Kleen Energy Plant on Feb. 8 to examine the accident site, conduct interviews and review documents. CSB’s investigation will focus on determining the regulations, codes and good practices that might apply to gas blows.
“In the meantime, we strongly caution natural gas power plants and other industries against the venting of high-pressure natural gas in or near worksites. This practice, although common, is inherently unsafe,” Holmstrom said.
“The safety issues raised by this accident are not limited to Connecticut,” Holmstrom said. “These issues are larger than any particular company, facility or individual. The U.S. has embarked an ambitious construction effort for new natural gas power plants. Thousands and thousands of workers across the country will be involved in constructing these plants. The safety of these workers and the nation’s energy independence are at stake as these gas-fired plants are built over the next 20 years.”
Holmstrom added that CSB is investigating possible alternatives to gas blowing, including the use of air, steam, nitrogen, water or combustion devices to safely destroy the gas.
“Companies must ensure that flammable gases are not vented into close proximity with ignition sources and workers. That is a vital safety message from all these tragedies,” Holmstrom said.