The Army says Dugway Proving Ground, where military weapons are tested, was locked down for hours because a small amount of a nerve agent was unaccounted for.

The military said in a statement Thursday the amount missing was less than one fourth of a teaspoon of VX nerve agent, which affects the body’s ability to carry messages through the nerves.

The missing vial prompted a lockdown late Wednesday afternoon that lasted until the agent was found early Thursday.

The Army says no one was in danger and the lockdown was ordered as a precaution. Between 1,200 and 1,400 people were inside the facility at the time.

Dugway is about 85 miles southwest of Salt Lake City.

UPDATE: From the Salt Lake Tribune:

Dugway spokeswoman Paula Nicholson said Thursday that the lockdown was ordered after a “routine inventory of sensitive material in the chemical laboratory. . . discovered a discrepancy between the records and the agent on-hand. As a precaution, the commander immediately locked down the installation and began efforts to identify the cause of the discrepancy. “

The vial was located, uncompromised, at 3 a.m. Thursday within the facility. Dugway officials did not specify exactly where the vial, containing less than 1 milliliter, or roughly a quarter-teaspoon of the agent, was found — nor did they detail how the vial had gone missing in the first place, or whether anyone was being disciplined as a result of the incident.

“All personnel are uninjured and safe. The public is safe as well,” Nicholson stressed.