LEXINGTON, Ky. -- The Pentagon has raised questions about the proposed design of a building that would destroy Kentucky's stockpile of chemical weapons, fears that threaten to delay construction.

Concrete was expected to be poured this summer at the munitions demilitarization building, the primary center at Blue Grass Army Depot in Richmond where Cold War-era rockets and other lethal weapons are set to be destroyed by 2017 to comply with an international treaty.

Blue Grass was already expected to be the last weapons site in the United States to destroy its stockpile of weapons, including sarin and mustard gas.

But John Schlatter, spokesman for Bechtel Parsons Bluegrass, the company in charge of the construction project, said Monday the timetable may have hit a snag after a Pentagon agency questioned the design of a room in the building that must be able to withstand an explosion.

In 1998, holes and unfilled wall sections were found in a similar explosion-proof room at another destruction site in Anniston, Ala., prompting a major repair job.

The Defense Department Explosive Safety Board told the company last week that it can't accept the Kentucky plans because they rely on a design regarding how the steel beams holding the concrete are connected.

Company executives expect to meet with the board this spring to discuss the engineering, Schlatter said. If the plans aren't approved by June, construction could be delayed indefinitely, he said.

"We're not going to do anything to sacrifice the safety," Schlatter said. "If there is ever a choice between safety and schedule, safety is the thing that wins out."

Calls were not immediately returned Monday from spokespeople for Blue Grass Army Depot and Assembled Chemical Weapons Alternatives, the Pentagon agency in charge of the neutralization process in Kentucky.

The Department of Defense Explosives Safety Board was created by Congress in 1928 after 21 people were killed in a disaster that virtually destroyed a Navy depot in New Jersey.