NEWPORT, Ind. -- The commander of the Newport Chemical Depot said the Army has plans in place for protecting a deadly nerve agent stockpile if its security guards go on strike.

The union representing security workers at the western Indiana depot agreed Thursday to a 60-day extension with contractor Mason & Hanger while negotiations continue, said Maxine Spendal, personnel director for the Lexington, Ky.-based company.

"This will give us time to continue negotiations and an opportunity to work out an agreement," she said.

Work began last year on destroying the more than 250,000 gallons of deadly VX nerve agent that has been stored at the depot about 30 miles north of Terre Haute for decades. The substance is so deadly that a tiny droplet can kill a person in minutes.

"In the unlikely event of a strike, I have a plan in place," said Lt. Col. Scott Kimmell, the depot's commander. "I can't get specific with you with respect to what my plan is. My plan does involve the Army at large."

Newport officials said that, as of Thursday, 15,371 gallons of the nerve agent had been destroyed, leaving a wastewater called hydrolysate that the Army has compared to liquid drain cleaner.