Galvanized by the Connecticut school shooting, some East Contra Costa school districts are planning safety improvements to their campuses, and many are making sure that employees know how to respond to an armed intruder.

School administrators from Antioch to Byron are reviewing their emergency procedures and taking stock of campus features that could be changed to make it harder for someone to slip onto the grounds unnoticed.

A maintenance worker at Oakley Union Elementary School District has been checking fences for holes and making sure that locks on the gates work, said Superintendent Rick Rogers, adding that since the Dec. 14 massacre most, if not all, of his principals have revisited the crisis-management protocols they go over with their staff at the start of each year.

Those maneuvers are essentially the same among all districts: The school office announces a lockdown over the public address system, directing teachers to lock their classroom doors, close any blinds, move children away from the windows and have them crouch under desks or behind bookcases until they get the all-clear.

Although Oakley Union uses code words to alert staff to danger without tipping off the trespasser, most local school districts have scrapped that practice in favor of broadcasting instructions that everyone immediately would understand even if they're not always on campus, as in the case of substitute teachers and parents who volunteer in classrooms.

Knightsen School District has stepped up its vigilance; although the district last year installed more fencing so there would be an interrupted barrier around the Knightsen Elementary campus, employees weren't locking all the gates once classes started, said Superintendent Theresa Estrada.

But they are now, she said, which means parents must go through the office to reach their child's classroom instead of taking a shortcut through one of the gates.

The district also is getting cost estimates for replacing the gates' padlocks with push bars so those on campus can escape more quickly, Estrada said.

Although Byron Union School District has a full-time sheriff's deputy serving as its school resource officer, Superintendent Ken Jacopetti nonetheless has been on the three campuses much more since the shooting, soliciting ideas on how it can beef up security.

Yard supervisors have asked for more walkie-talkies and keys to the gates so they each can have one, requests Jacopetti says he'll honor.

He's also considering having the schools keep every classroom locked all the time and installing doors to the front offices that visitors can't open unless they're buzzed in.

Oakley's Freedom High School will be getting classroom doors that lock from the inside like those at Heritage and Liberty high schools in Brentwood -- a safety measure that Liberty Union High School District was planning to implement even before the attack, said Superintendent Eric Volta.

Similarly, Antioch Unified School District has used part of an 18-month federal emergency readiness grant to train its principals what to do if someone opens fire on campus by having them act out various situations.

Barricade the classroom doors and, if the shooter still forces his way in, "fling everything you can at them and try to escape," said Tim Forrester, associate superintendent of business and operations.

Even more basic is reminding school employees to watch for individuals who might not belong on campus, those who aren't wearing a visitor's badge or a lanyard with their identification.

Antioch Unified personnel are supposed to question strangers who are lacking credentials, said Superintendent Donald Gill, noting that he sometimes is approached by employees who don't recognize him when he visits campuses.

He acknowledged that it can be more difficult to monitor high school campuses, however, because a potential assailant can blend in more easily there than among young children.

Police will be reviewing the emergency procedures of every school in Brentwood Union School District when classes resume next month as well as making sure that administrators not only know what they're supposed to do if a gunman starts firing but that teachers do, too.

Employees participate in lockdown drills at least once a year, and police, including the district's part-time school resource officer, practice finding and disarming a campus shooter in staged scenarios, said Brentwood police Chief Mark Evenson.

Having an armed and uniformed school resource officer on campus with a marked patrol car parked at the entrance makes would-be attackers think twice, he added.

"I think they're a huge deterrent," Evenson said. "A lot of these active shooters, they're not there to confront police."

Since the rampage in Connecticut, he said his department has started developing a training exercise that will have officers and school personnel dissect a hypothetical situation, discussing such things as where the school would evacuate students, places where parents and the news media could gather, and who would be the liaison between the police and school district.

Whatever steps a school district takes to avert disaster, however, those responsible for students' safety acknowledge that there's no guarantee that someone bent on destruction couldn't breach the safeguards.

"If you've got a crazed person ... there are things you can do, but you still might get hurt doing them," Forrester said. "There's no 100 percent fail-safe with anything."

Contact Rowena Coetsee at 925-779-7141. Follow her at Twitter.com/RowenaCoetsee.