NEWPORT – A gasket failure caused caustic wastewater to spill at the Newport Chemical Depot, and VX destruction will not resume for at least two weeks while workers replace all of the gaskets in two reactors, the Army said Thursday.

The Army’s preliminary investigation into the Oct. 29 spill of 490 gallons of the wastewater, called hydrolysate, shows it was caused by a material failure of a gasket or a mechanical failure possibly involving improper installation or alignment of the gasket, the Army announced.

The gasket that failed is in a recirculation loop used to sample each batch of hydrolysate to make sure it contains no measurable amounts of VX. Each of the two chemical reactors used to destroy the VX contains 44 gaskets, so a total of 88 must be replaced, spokeswoman Terry Arthur said.

“To assure ongoing system safety, we are taking this opportunity to change out all gaskets in the reactor system,” Rick Rife, project manager for contractor Parsons Technology Inc., said in a prepared statement.

The VX is destroyed by mixing it with heated water and sodium hydroxide in the reactors, creating the hydrolysate, which the Army has compared to liquid drain cleaner. The hydrolysate spilled in a contained area. No workers were injured.

The spill nearly two weeks ago halted operations at the disposal facility 30 miles north of Terre Haute, so the additional time to replace all of the gaskets means VX destruction will be shut down for about a month, if not longer.

The Army’s Newport project manager, Jeff Brubaker, said testing performed in 1997 showed the gaskets were compatible with destruction of the VX.

“As part of the investigation process, a follow-up analysis is under way to verify whether the data previously reported is consistent with the actual hydrolysate from the Newport process,” Brubaker said.

In May, work began to destroy Newport’s more than 250,000 gallons of VX, a substance so toxic that a single droplet can kill a healthy human. So far, 6,571 gallons have been destroyed.

The project was halted in June after a leak resulted in a spill of about 30 gallons. Work resumed in August.