If students hear rumors about a major disaster tomorrow, they shouldn't be alarmed.

Tucson law enforcement, UAPD and local emergency aid agencies will test how quickly they and administrators can respond to a disaster during a four-hour drill held on campus tomorrow.

Police are keeping event details and scenarios secret until hours before the drill. At least 20 students will take part in the event as role players, said UAPD Cmdr. Brian Seastone.

The drill will take place on the west end of campus from Old Main to the Arizona State Museum. Other buildings that will be involved are Centennial Hall and the Communication and Center for English as a Second Language buildings. Classes in those buildings have been relocated.

Although UAPD is in charge of the exercise, the Tucson Fire Department, Tucson Police Department, the Pima County Health Department, and the Department of Homeland Security may be called in for practice as well, Seastone said.

This will be one of the largest disaster drills ever held on campus and is a culmination of years of preparation between university officials and UAPD. In previous years, both have worked together to discuss emergency response plans, and tomorrow's exercise will put them into practice, Seastone said.

"The university has done a lot of table-top exercises over the years in various departments," he said. "This is the first time that we will have a drill of this magnitude."

University police will use the drill not only to practice, but also to find areas that need improvement.

"What we are hoping to accomplish out of this is to see how well we have worked with the university community," Seastone said. "The purpose of these exercises is to always improve the amount of safety we can provide."

To keep the exercise as realistic as possible, the 20 student role players will not know any details until just prior to the event. Seastone asked for volunteers from ASUA and other student groups.

ASUA Sen. Nick Bajema and other ASUA senators were approached about a month ago. Bajema jumped at the chance to take part in the drill.

"It'll be a good practice to keep the campus safe," he said. "I'm interested in the persuasions that they're going to take."

Dean of Students officials have also been kept in the dark about the scenarios. Alexis Hernandez, associate dean of students, said this will help keep police and university officials from skewing the results of the drill.

"If you knew about it beforehand, would you be checking on how the response is or checking on what you're doing for the rest of the day," he said.

Although the drill is based on events that have occurred on campus, it is not directly related to any one particular event, most notably the UA Nursing School shootings one year ago, Seastone said.

"This has been in the planning stages for a number of years," he said. "We feel that it is time to do the actual exercise. It is not because of the shootings."

Emergency and law enforcement vehicles will be stationed throughout the west end of campus during the drill. There will also be signs posted to alert the public as the exercise progresses.

Seastone said the drill will be instrumental in gauging many aspects of campus safety during disaster situations. Although he could not comment on what scenarios will be faced, he did say that UAPD and the university will hold more drills like this in the future.

"I anticipate that we will have more of these over the years," he said. "We want to make it as real as possible."