The main activities will take place inside a vacant building at the Long Meadow Shopping Center at the intersection of Eastern Boulevard and Leitersburg Pike, Kelly said.
Officials expect minimal traffic impact from the drill, but there will be signs to notify passers-by of the events, Kelly said.
The point of the drill is to improve how first responders and coordinators from local, state and federal agencies work together in a crisis, Kelly said.
Kelly said the participants will act out two training scenarios next week. In one, emergency responders will act out a response to a fake chemical release. In the second scenario, the responders will act out the safe disposal of chemicals discovered in a make-believe apartment of a terrorist cell.
Kelly said FBI agents will brief the drill participants Monday afternoon, and test coordinators will run through safety procedures before the drill begins.
The exercise begins at about 6:30 p.m. Monday with the fake chemical release, Kelly said.
Trainers will tell emergency service workers participating in the event how conditions would be changing in a real event on a moment-to-moment basis.
For instance, Kelly said, a trainer might tap a firefighter's shoulder and tell her she had been knocked out by the chemical. The firefighter will be taken to Washington County Hospital, where she will tell participating doctors what symptoms she has.
The doctors then would have to properly "treat" the mock patient by either washing off an indicator substance or explaining to trainers how they correctly would treat someone who actually was suffering from those symptoms, Kelly said.
At the same time, first responders will have to talk to EPA workers also participating in the drill, and the federal workers also will have to go through motions like they would if a real emergency were to arise.
Kelly said no part of the hospital would be closed during the drill, and no one should notice the drill. He said if a true emergency arises during the drill, the local agencies would drop the drill and make their routine calls.
The drill will end at about 10 p.m. Monday, and pick up again Tuesday morning. Kelly said the drill could end Tuesday afternoon if things go well, but trainers have scheduled the drill to run until Wednesday at 2 p.m. if extra time is needed.
Local participants include members of the Hagerstown police and fire departments, the county health department and Washington County Hospital.
Also included will be the Washington County Special Operations Unit, which handles hazardous material, and the Washington County Special Response Team, which is the county's quick-strike police squad comprised of officers from Hagerstown City Police and the Washington County Sheriff's Department.
Giffin said that aside from a large amount of people and emergency vehicles parked at the shopping center, residents should not be affected.
"It's definitely good to have drills like this," Giffin said. "It gives us a chance to watch how each other works, and to work cooperatively."