The federal Chemical and Safety Hazard Investigation Board

it has probably zeroed in on what caused the fatal June 11 explosion at a Goodyear plant here: a blocked pressure-release valve.

Investigators have made two week-long visits to the site. Their work continues, but they'll be focusing on the valve.

"Companies should be vigilant to ensure that pressure-relief systems are adequate and are properly maintained and operated to continuously protect equipment from over-pressure," CSB chairman John Bresland said, in one of those hard-to-argue-with statements.

Congressman Gene Green was quick to take some of the credit. His office issued a press release saying Green had called for the CSB to investigate.

"I am relieved that the CSB heeded our call to proceed with an investigation of this tragic accident," he said.

The blast killed one worker and injured seven others.

-- Richard Connelly