New London — For the first time, the Coast Guard and local law enforcement agencies practiced on Tuesday how they would respond to a shooting on the Coast Guard Academy grounds.

Many who took part said it was important to hold this type of drill at the academy because of the recent shootings at military installations and schools.

The mass notification system that was used to notify everyone at the academy about the lockdown during the drill was installed after the shooting at Virginia Tech in 2007. It was tested just days before 20 children and six adults were killed in December inside Sandy Hook Elementary School in Newtown.

Last month, a gunman killed 12 people at the Washington Navy Yard, and last week, two people were shot and wounded at an armory outside a Navy facility in Tennessee.

"Certainly, as secure as this base is, these events could unfold here," said Coast Guard Cmdr. Rob Oatman, who directed the exercise and who serves as the academy's chief of information services.

At sea, Coast Guardsmen often practice for fires and collisions, Oatman said. "I think we've become complacent shoreside," he said. "We think, 'What could really happen here that would be that bad or challenging?' So it's good to remind ourselves events can happen, you can have a fire, you can have an act of violence incident. And the more you prepare for it, the less it becomes a source of anxiety."

New London Fire Chief Henry E. Kydd Jr. said these drills should be done more often, "with the way things are going on in our world."

"This is going to be more commonplace," he said, referring to the potential for future incidents.

The drill began shortly after 9 a.m. with a "report" of a possible active shooter at the academy. Many of the first responders knew the scenario would start with a shooter in an auditorium in Dimick Hall, where a faculty member was conducting a lecture with 16 cadets present.

But because so many agencies agreed to participate, Oatman said, a second shooter scenario was added inside Smith Hall, an academic building that connects to Dimick, to make the drill more complex. The first responders were not briefed about that change.

About 80 people from 30 agencies converged on the campus, including police and fire personnel from New London, police officers from Norwich, Stonington, Enfield and Vernon, and members of the FBI, Connecticut State Police, Office of the Chief State's Attorney, Connecticut Air National Guard and several Coast Guard units.

An announcement was broadcast over the mass notification system that "an emergency condition has been reported" and lockdown procedures should be followed. Everyone on campus was instructed to find a secure location, turn off the lights and avoid windows and doors.

Cadets ran out of the buildings as teams of law enforcement officers carrying replica guns ran in. They pursued both of the shooters — volunteers from the Law Enforcement Council of Connecticut — through Smith Hall.

The participants spoke to each other over handheld radios and tried to keep track of the teams, the shooters, the number of people injured or killed and the progress in clearing the rooms. Medical personnel set up a triage area outside to treat the victims.

Oatman said there were a lot of successes and failures throughout the drill, which ended at about 10:30 a.m. He said he had expected some communications issues since the agencies do not all use the same radio system. The academy also will have to figure out the best way to manage effectively the different mutual aid groups when they rush in to help, Oatman said.

He said he already has received useful tactical feedback about entering buildings, clearing rooms and treating victims.

"We've got people thinking on base about an act of violence incident," he said. "... Even if they spend 10 minutes and they say, 'Here's where I would go, this is what I would do,' then this drill was a success."

State police Master Sgt. Jim Gilman, who entered the buildings, said the biggest setback was communications but that overall, the exercise was a good training experience and the agencies worked well together.

Rear Adm. Sandra L. Stosz, superintendent of the academy, said drills like this have not been done in the past largely because they are so disruptive of the academic day and the activities on campus.

When the mass notification system was tested last year, some faculty and staff complained the warnings were frightening and said they did not want to hear them, Stosz said. The complaints stopped after the shooting in Newtown occurred a couple of days later.

"A lot of times, people just want to pretend it is not going to happen," Stosz said. "I'm an operator, I come from a ship, we do drills all the time. And I want to do drills on this so we develop a resilient mentality here at our academy. We should be leading the way on resilience. We should be leading the way on response to threats and active shooters."

Stosz said she also thinks it's important that the local agencies are familiar with the campus. To further tighten security on campus, the academy is installing a swipe card access system in the Chase Hall barracks, she added.

The drill cost the academy about $4,500, which includes safety gear, props, flags and signs, according to the academy. That figure does not include the cost to the agencies, who responded voluntarily.

"It's a sad development that people who are in national security facilities have to add this to their portfolio of training," U.S. Rep. Joe Courtney, D-2nd District, said. "But clearly it's necessary based on what has happened. I think the folks at the academy are being very smart and proactive."

j.mcdermott@theday.com