HERMISTON -- The last emergency drill scheduled at the Umatilla Chemical Depot is Tuesday.
Residents in Benton, Umatilla and Morrow counties will hear tone alert radios and sirens, accompanied by a test message, about 9 a.m.
Drivers on interstates 82 and 84 will see test messages on highway reader boards.
After 20 years of emergency drills, this is expected to be the last Chemical Stockpile Emergency Preparedness Program drill.
Disposal of the last of the mustard chemical weapon agent stored at the depot is expected to be done by the end of the year.