An explosion that left workers suffering from first, second and third-degree burns and other injuries has resulted in citations for two companies, according to OSHA.

The agency charged both U.S. Steel Corp. and Power Piping Co. with failing to provide an effective energy control procedure, leading to a July, 2010 explosion at U.S. Steel's Clairton Works facility in Clairton, Pa.

As a result of an investigation following the incident, OSHA cited U.S. Steel for two willful and 11 serious violations, with a total penalty of $143,500. Power Piping Co., which was contracted by U.S. Steel to provide steam fitting services at the site, was cited for six serious violations, with $31,500 in penalties.

"U.S. Steel and Power Piping did not have the proper controls in place to prevent worker exposure to hazardous energy," said Robert Szymanski, director of OSHA's Pittsburgh's Area Office. "These violations must be abated immediately to prevent future incidents."

The alleged willful violations for U.S. Steel involve the company's failure to provide an effective energy control procedure. A willful violation exists when an employer has demonstrated either an intentional disregard for the requirements of the law or plain indifference to employee safety and health.

That company's alleged serious violations include a lack of fall protection, inadequate lockout/tagout to prevent the inadvertent release of energy, a deficient process safety management program, and failure to implement an emergency response plan, evaluate respiratory hazards, use flame retardant gloves and use approved electrical equipment. A serious citation is issued when there is substantial probability that death or serious physical harm could result from a hazard about which the employer knew or should have known.

Power Piping's alleged serious violations include inadequate energy control procedures, a lack of flame-retardant hand protection and the company's failure to evaluate the respiratory hazards posed by coke oven gases.