Workers have pinpointed the source of the nerve gas leak discovered last week at the Blue Grass Army Depot in Madison County.

A small amount of liquid GB, or sarin, was coming from a rocket in an igloo at the depot. The leak was found during a routine check of the air in the igloo. After that, Blue Grass Chemical Activity Toxic Chemical workers went into the igloo and inspected its contents to find the source.

A large filter was connected to the igloo to make sure that none of the gas escaped into the atmosphere, and the leaking rocket and two others stacked under it have been placed in leakproof containers.

The igloo is to be monitored to ensure that no more vapors are escaping, then the container will be taken to another igloo that is monitored for leaks every workday, according to a press release from the U.S. Army Chemical Materials Agency.

The leak did not pose a risk to citizens of the area, the press release stated.