Ascension Parish sheriff deputies on Tuesday arrested a contractor with a Pennsylvania-based tank company over the bomb threat that forced the evacuation of the PCS Nitrogen plant on the 13th anniversary of the 9/11 terrorist attacks.

Terry Randal Cox II, 34, 5848 S. 3000 West, Roy, Utah, made the threat against the fertilizer and phosphate complex on River Road in Geismar from his cellphone, deputies said in a statement Wednesday.

Chief Deputy Tony Bacala said Cox was an employee of Fisher Tank Co., which is based in Chester, Pennsylvania, and was working at PCS Nitrogen at the time the threat was made.

About 540 employees at the plant had to evacuate and were sent home for the day, Bacala said.

He said the bomb threat was not specific, only that there was a bomb in the plant and that it was going to go off.

Bacala said Cox has not admitted he made the call, but Bacala said that in addition to Cox’s cellphone number, deputies have a recording of the call in which Cox’s voice has been identified.

Cox was arrested on one count of terrorizing and was booked into Ascension Parish Prison near Donaldsonville. As of Wednesday afternoon, Cox was awaiting bail to be set.

Fisher Tank’s offices in Pennsylvania and Alabama were closed Wednesday by the time calls for comment could be made. Messages were left in voice mail boxes at each location.

A worker answering the telephone at PCS Nitrogen said no one was available to comment Wednesday evening.

The 9/11 anniversary has typically been one of remembrances and, more so in earlier years, heightened law enforcement presence. According to a variety of news accounts, a number of bomb threats were made this year around the 9/11 anniversary, including at schools, the U.S. Marine Corps Base in Quantico, Virginia, the rebuilt World Trade Center in New York and the London Bridge subway station in London.