Anti-terror exercise starts Oct. 15

Most of the public won't even be aware that part of the largest federal "terrorism preparedness exercise" ever staged will take place in Tucson and Phoenix later this month.

The U.S. Department of Homeland Security will conduct terror response drills with area law enforcement, emergency medical, hazardous materials and fire crews from Oct. 15-19.

Phoenix and Portland, Ore., along with the territory of Guam, will be the central locations for "TOPOFF 4," the fourth in a series of exercises by federal, state, county and municipal agencies to coordinate responses to apparent terror-related events.

TOPOFF is an abbreviation for Top Officials, the designation given to the program by federal Homeland Security officials.

The operation will include Pima County and Tucson law enforcement agencies.

The drill in Arizona will be low-key, Michael Murphy, public information officer for the Arizona Department of Homeland Security, said Wednesday.

"For most people, they won't even know there is an operation taking place," Murphy said.

The scenario will be that a "dirty bomb" has been detonated, spreading radioactive materials and endangering the public health.

A dirty bomb, a device packed with radioactive materials, would be detonated with conventional explosives. The radioactive materials would be dispersed into the air by the detonation.

The exercises in Arizona will be aimed at improving communications among participating agencies "so they know how to work together and communicate together," Murphy said.

Tucsonans and Phoenicians won't see anything like the full-scale training event that will take place in Portland that same week, where agencies will publicly respond as though a terror attack had taken place.