Sept. 24 (UPI) -- Months after gunmen killed 27 people at high schools in Parkland, Fla., and Santa Fe, Texas, schools across the United States have implemented new safety procedures.
School districts have been trying to stem gun-related violence for decades. In the wake of the 1999 shooting at Columbine High School that killed 13 in Colorado, for instance, there was a flurry of new metal detectors and a boost in armed security on campuses.
But after the Feb. 14 shooting at Parkland's Marjory Stoneman Douglas High School, the teen survivors demanded action. Students around the world joined them. Policymakers, parents and celebrities supported them. Some states moved immediately to change laws governing gun ownership and school security.
Students across the country have returned to school over the past few weeks facing a slew of unfamiliar rules and safety procedures -- new surveillance cameras, new alert systems and in some cases, armed teachers.
Here are some highlights from around the United States.
Marjory Stoneman Douglas High School
MSD students started the school year Aug. 15 with 52 new security cameras. A plan to add metal detectors was scrapped.
The school also ditched a new requirement instituted in the final weeks of last school year -- see-through backpacks. Students complained that rule violated their privacy.
In addition, students must wear IDs at all times, campus security has increased and school entrances were limited to four.
MSD also altered the fire alarm tone, added four new security officers, more school resource officers, and more gates and locking hardware.
Statewide, Florida passed a new law requiring an armed security guard on each school campus. Prior to the law, there were 1,500 officers in Florida's Department of Education for about 3,800 public schools.
Santa Fe High School
Students returned to Santa Fe High School -- about midway between Galveston and Houston -- on Aug. 20, about three months after a shooter killed eight students and two adults at the school.
Since the May 18 shooting, the school district created a threat assessment team, reduced entry points to the high school, staffed those entry points with armed officers and metal detectors, installed panic buttons in classrooms and required that all staff and students wear identification at all times.
Over the summer, the Santa Fe Independent School District board, which oversees two elementary schools, one junior high and a high school, voted to spend $1 million on the upgrades. The costs included $650,000 for the panic buttons, $150,000 for locks inside classrooms and $250,000 to remodel the high school's front entrance.
Santa Fe ISD isn't the only school district to implement an alert system.
In Illinois, more than 20 private schools installed pale blue pull boxes -- similar in appearance to fire alarm pull boxes. The boxes, if pulled, alert police to the presence of an active shooter.
St. Benedict's Preparatory School spent $90,000 on its new alert system, which includes 30 of the boxes throughout the campus, the Chicago Tribune reported.
The company that created the so-called BluePoint alert system said more than 150 schools use it across the country. Some school employees also can engage the alert system using fobs they wear around their necks.
An alert system at the Columbiana School District in Ohio is coupled with another, unique deterrent of gun violence -- a non-lethal defense system called a Threat Extinguisher.
The devices look similar to fire extinguishers but instead fire off pepper spray. When removed from their bases, they set off an alert, notifying police and officials about an on-campus threat and the location of said threat.
According to the National Conference of State Legislatures, which tracks state laws across the country, the majority of states prohibit firearms from being carried on school campuses, with some exceptions.
More than a dozen states have laws allowing school employees other than security guards to carry guns under some conditions: Alabama, Arkansas, Colorado, Florida, Idaho, Indiana, Kansas, Missouri, Oklahoma, Tennessee, Texas, South Dakota and Wyoming.
Though each of these states allows armed employees, not all school districts allow the practice and not all allow teachers. It's up to each district to vote on arming teachers, and some, like Florida, Missouri, Oklahoma and Tennessee, must undergo required training.
Some school districts in other states allow non-teaching school employees to carry guns, like Toppenish School District in Washington, where Superintendent John Cerna carries a gun and allows at least one administrator and one security guard in each school to be armed.
Another school district in rural Indiana, Jay Schools in Portland, is preparing to arm its teachers. Superintendent Jeremy Gulley told UPI earlier this month that the district purchased firearms, installed biometric safes and trained an undisclosed number of teachers and staff. He said he expects the school board to formally adopt a policy allowing teachers and staff to be armed later in September.
"This plan was thoughtfully considered and thoughtfully executed," Gulley said. "We've had a lot of community support."
Jay Schools, which serves about 1,100 students, would be the second district in Indiana to adopt a policy to arm teachers.
In the Charleston County School District in South Carolina, officials installed bullet-resistant classroom doors in three schools. The Post and Courier reported that the district hopes to one day installed the protective barriers in all schools.
Tony Deering, who owns R2P Innovations, which creates and installs the doors, estimates each costs $4,000.
Students at Hamilton City School District in Ohio, meanwhile, returned to school this year with a new rule in place -- all backpacks must be kept in lockers during the day. Teachers there also took training in how to stop heavy bleeding during a potential attack.
"Every time there's an incident somewhere in the nation, it's likely to send out shock waves," Hamilton City School District Superintendent Larry Knapp told USA Today. "And we learn from those incidents -- from what the bad guys are doing -- different ways that we can protect ourselves."
The training mimics a program Department of Homeland Security Secretary Kristjen Nielsen supports -- one that prepares students for how to help injured victims during a shooting.
"We recently established a $1.8 million grant to enable schools and other groups to train high school students with the skills necessary to stabilize the injured and control severe bleeding," she said during an August school-safety meeting for Trump administration officials.
A previous version of this story incorrectly reported that metal detectors were installed at Marjory Stoneman Douglas High School. That plan was scrapped.