Security was stepped up at New York City's Benjamin Cardozo High School on Friday, the day after a student was found with a loaded gun and arrested after allegedly threatening a shooting. 

Police said the 16-year-old brought a loaded 9mm handgun to the school in Bayside, Queens, in a backpack on Thursday and was charged with criminal possession of a weapon and making terrorist threats, which prompted Friday's upped security.

The student, from Springfield Gardens, was arraigned as a minor in Queens Criminal Court and faces up to four years in prison if granted youthful status in court. 

Metal detectors in use day after student found with loaded gun

Students arriving at Cardozo High School waited in line to walk through metal detectors Friday, part of the new security measures that were added after what police said was a foiled terror plot. 

It raised questions about school security and if scanners should have already been in place. 

The City Department of Education said the use of scanners and metal detectors is handled by the NYPD's School Safety Division under protocols that were created in 2016 and has not been updated since. 

"There was scanning this morning, and there will continue to be for the foreseeable future," NYPD Commissioner Jessica Tisch said. "We've also of course beefed up our deployments at the school, including both uniform officers as well as our school safety agents." 

Greg Floyd, president of the union representing school safety officers, Local 237, said in a statement the city budget has left them short by more than 2,500 officers. The result is "not enough personnel to even operate more scanners. It can only get worse," he said. 

The NYPD said 84 city schools have permanent scanning out of 1,200 middle and high schools in the system. 

CBS News New York requested interviews with school safety officials at DOE and NYPD, but both declined. 

A DOE spokesperson said in a statement, "We are offering additional security and supports to the school community today - and in the coming days - and are working closely with the NYPD regarding follow-up actions." 

NYPD school safety protocols

According to the protocols created in 2016, principals can request scanners after weapons are found at a school.

It is a four-step process, which the principal first must run by the school safety committee, school leadership, teachers, teachers union, staff, students, parents, school safety agents, superintendent and borough safety director. 

All must give the green light before the process moves forward. That's why, in most cases, it takes something like the incident at Cardozo High School to get scanners installed. 

After last month's mass shooting at a school in Minneapolis, the DOE's security director, Mark Rampersant, told CBS News New York, "This is something that concerns us in New York City public schools on a daily basis as one of the largest school systems in the country. As it relates to technology, we're always looking for innovative ways to ensure safety and security for our young people."

Student reactions to school's heightened security

Sebastian Camilo, a senior at Cardozo High School, said he would have felt safer if the scanners were installed prior to Thursday's scare. 

"It's a day after. No one's going to bring anything, realistically, a day after, knowing that they're doing metal detectors," Camilo said. "Why not just do it before or do a better job making sure no one has anything, like no weapons or anything like that. They're more focused on putting away our phones. I feel like wrong priorities there."

"I feel really surprised, and I feel really shocked too, and scared, because I feel like nobody should have to go through any concerns like this. I feel like we should all learn in a safe environment where we don't have to worry about being shot," Cyrus Cordero, another student, said. 

"Really uncomfortable, honestly. Because we're a no-scan school, that means we're not 100% safe," Milan White, another student, said.