MIDDLESEX, N.C. — A sole worker was unaccounted for Friday after an explosion at a manufacturer of wastewater treatment chemicals in Nash County, the Middlesex chief of police said.

A fire tank exploded at Pencco, Inc., on U.S. Highway 264-A in Middlesex, at around 10 a.m., according to the fire marshal. He said two people were on duty at the time, but he did not identify either person.

The explosion could be heard and felt in communities from Zebulon to Spring Hope to Bailey, and people chimed in on Facebook to wonder what caused it.

Pencco's corporate offices are in Texas. The company also has a location in California.

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