Pine Bluff Arsenal spokeswoman Cheryl Avery says laboratory tests confirmed a trace amount of chemical agent vapor during routine air monitoring of a ton container storage igloo late Monday.

The container stored in the igloo contains the chemical agent mustard. She says highly trained and experienced personnel entered the igloo and isolated the container.

Operations are ongoing to seal the container, which will be closely monitored while it awaits disposal.

Avery says the event never posed a threat to arsenal employees, the local community or the environment.