Managers of Deseret Chemical Depot near Stockton, Tooele County, are trying to determine why a low level of VX nerve gas vapor showed up inside a depot laboratory Tuesday afternoon.

At 2:40 p.m., about a minute after two monitoring technicians left the room, an alarm went off inside the Agent Vault Room of the depot's Chemical Assessment Laboratory, said depot spokesman Chuck Sprague. Everyone in the lab donned gas masks and all were escorted from the building, located one mile west of the Army's chemical weapons incinerator.

The incinerator temporarily shut down all operations involving toxic material while the event was studied, he added in a press release.

The technicians were taken to the facility's medical clinic, where they were observed and then released. Asked if they showed symptoms of exposure to nerve agent, Sprague said he assumed they were not exposed or they wouldn't have been released that soon.

"One of the technicians had entered the area to check personal protective clothing, cleanliness of the room and to prepare for an agent sample" that was on its way from the incinerator, says the press release.

Sprague told the Deseret Morning News the technicians had not lifted or taken anything while in the laboratory. They were simply making checks. After they left, and nobody was in the room, the alarm sounded, indicating VX vapor was detected.

No munitions are stored in the room, but it does have small vials of VX nerve agent used for testing purposes.

Why the alarm rang remained a mystery on Wednesday.

"I went to a meeting this morning and they just don't know" the cause, Sprague added. A team of experts was checking to see if they could find out what happened.

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