Poor Drainage Faulted in Fatal Blast: CSB

Friday, March 13, 2015 @ 01:03 PM gHale


The July 2010 explosion that killed two workers at Horsehead Corp.’s Potter Township, PA, plant was likely the result of a faulty drainage system that turned zinc refining equipment into a pressure cooker that eventually exploded, according to a report released Wednesday by a federal safety agency.

“Human factors played a dominant role” in the Beaver County incident, adding that “problems in the hours before the accident were not observed and acted upon,” said a report from the U.S. Chemical Safety Board (CSB).

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William Hunter, a U.K.-based metallurgist who managed zinc smelters for 30 years and has investigated accidents at other zinc refineries, authored the report. The basis of the report focused on witness interviews, company evidence, laboratory test results and other information, the safety board said.

Horsehead contested the findings in a four-page letter attached to the 51-page report. The company faulted Hunter for not visiting the site following the explosion, for not interviewing witnesses personally and for failing to inspect the debris.

“There really isn’t any definitive data to identify a root cause,” said senior vice president Ali Alvai.

A safety board official defended the methodology. “The report is extremely thorough and technically rigorous,” said senior adviser Daniel Horowitz.

In comments attached to the report, a United Steelworkers union official said workers had complained about problems with a sump pump that would drain material from a column where the zinc ended up refined. The blockages built up pressure inside the equipment and caused the blast, the report concluded.

“The union safety committee and union officials would constantly tell officials that something needed to be done about the blockage of the sump pumps. … The employees kept on complaining, but the company would not listen,” USW Local 8183 president John Jeffers wrote.

The CSB report said there were problems with the sump pump before the explosion.

“Given this history, management should have put out a general warning that [it] was functioning abnormally, that there was a potentially hazardous condition at the sump and that extra care should be taken,” Mr. Hunter said.

Technology used in the refining process at the plant dated from the 1920s and no longer sees use in the U.S., although it does see action in China and other countries, the report noted.

James Taylor, 53, of Aliquippa, PA, and Corey Keller, 41, of Newall, WV, died in the July 23, 2010, explosion. Horsehead paid $42,000 in fines in 2011 to settle citations brought by the federal Occupational Safety and Health Administration.

Horsehead has since closed the plant and transferred production to a new plant in Mooresboro, NC.

Shell Chemical is purchasing the Potter site and has proposed building an ethane cracker plant there that will convert natural gas liquids into a feedstock for the petrochemical industry.



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