Plant remains shut after explosion

NEW CASTLE, Pa. — International Specialty Alloys at 599 Northgate Circle remained evacuated Thursday after an explosion rocked the facility Wednesday morning, said Joy Chandler, a spokeswoman for the company.

The explosion caused one serious and three minor injuries, the fire department said. The seriously injured employee, Jeffrey Grimes, was taken to Mercy Hospital in Pittsburgh. He was in the Birmingham Trauma and Burn Center in serious condition, a spokesman said.

Chandler said engineers were in the facility Thursday.

The cause of the explosion at 9:34 a.m. Wednesday is under investigation but appears to be accidental, the fire department said. The material involved was likely a combination of aluminum powder and niobium oxide, both of which are used in the ISA manufacturing process.

ISA is a producer of master alloys used in the aerospace, superalloy and computer industry. It uses, among other processes, specialty atmosphere heat treatment furnaces to provide a full range of products to many industries worldwide, according to its Web site.