HERMISTON -- A depot chemical operations monitoring crew detected trace amounts of mustard chemical agent vapor today inside a depot storage structure containing ton containers.

The trace of mustard chemical agent was detected during routine monitoring.

The storage structure, commonly called an igloo, has a "passive" filtration system that prevents chemical agent vapor from escaping outside the structure. However, as a further protective measure, a powered filtration system has been installed. A team of specially-trained workers will enter the igloo to isolate the suspect ton container and determine future actions.

Even though the readings are so low they are not harmful to the public or the environment, depot officials notify the public when such incidents occur. They also notify off-post emergency operations centers in Umatilla and Morrow counties, Ore., Benton County, Wash., those in Oregon and Washington states, the Confederated Tribes of the Umatilla Indian Reservation and the Oregon Department of Environmental Quality.