The U.S. Chemical Safety Board said Thursday it will investigate this week’s fatal well explosion in Oklahoma, the deadliest shale-drilling accident since the start of the shale boom.
Five oil rig workers were killed in the Monday morning explosion, which occurred east of Oklahoma City at a natural-gas well drilled by Patterson-UTI Energy Inc., a Houston-based company, for owner and operator Red Mountain Energy of Oklahoma.
Investigators from the Chemical Safety Board arrived Wednesday at the site of the explosion, and met with representatives from both companies.
“CSB investigators will continue to meet with well service providers and the well site consultant company that had employees on site at the time of the incident,” the board said in a statement Thursday. “Evidence preservation and collection is the initial focus of the investigation.”
The Chemical Safety Board is an independent federal agency that investigates chemical accidents. The agency’s board members are appointed by the president and confirmed by the Senate.
The Occupational Safety and Health Administration has also opened a federal investigation into the explosion. The Associated Press reported Thursday that 10 workers have died over the past decade at well sites used by drilling contractor Patterson-UTI.
The company has been fined nearly $367,000 over the past 10 years for more than 140 safety violations. But multiple deaths from one incident are rare in drilling and fracking for oil and gas since the shale boom.
In 2015, three workers died from an explosion at an oil well south of Midland, Texas, in the Permian Basin.
Before this week, that incident had been the deadliest explosion in the modern history of the shale industry, the Wall Street Journal reported.
The U.S. has become the world’s largest producer of natural gas.
