Brittle Steel Suspected In Tank Collapse With AM-Fuel Spill, Bjt
PITTSBURGH (AP) _ Cold weather and brittle steel could have led to the tank collapse that sent diesel fuel gushing into two major rivers in three states, metallurgists said.
The first crack in the 4-million-gallon Ashland Oil Co. tank near West Elizabeth might eventually be traced to a faulty weld causing ″a fracture that ran through the whole side and just opens up,″ said metallurgist Alan Pense, associate dean of engineering at Lehigh University.
Pollution from the accident moved down the Monongahela River and stalled in the Ohio River, menacing Steubenville, Ohio and Wheeling, W.Va.
None of the experts, quoted by the Pittsburgh Post-Gazette on Friday, had examined the crumpled tank.
Ashland spokesman Roger Schrum declined to speculate about the cause or comment on the specialists’ remarks until investigations are completed by Ashland engineers and the U.S. Bureau of Standards.
Descriptions of the tank failure suggest a ″classic brittle fracture,″ Pense said.
When steel for the 40-year-old tank was made, American steel producers made metal more brittle than today’s products, he said. ″The steel hasn’t changed or weakened because it’s older. It was like that to start with,″ Pense said.
Manufacturers changed the composition of steel plate after freighters developed cracks in the frigid North Atlantic during World War II.
″We really learned about toughness during World War II,″ Pense said. ″Maybe 1,000 ships developed cracks, and when that happened there was a concerted study on a national level.
″There was a realization ... that steel goes through a transition in behavior from tensile to brittle in cold weather,″ he said.
A cold snap had dropped the temperature to 7 degrees last Saturday, when the tank burst at 5:10 p.m.
″The toughness of steel goes down with cold,″ said metal specialist Regis Pellous of the Massachusetts Institute of Technology.
″The cracks are very tiny, and if the material isn’t the right kind of toughness, they can explode into a complete fracture and tear the whole thing apart,″ said Steven Fenves, a civil engineering professor at Carnegie Mellon University.
″It’s scary,″ he said. ″It’s what every structural engineer is afraid of.″