Teachers in some parts of Florida can now carry guns inside the classroom.

The new policy comes just over a year and a half after a gunman opened fire at a high school in Parkland, killing 17 students and staff in the deadliest high school shooting in American history. The most recent version of the programme was approved in the Florida legislature in May, after a contentious debate that included shouting and crying among politicians, the Miami Herald reports.

With that passage, teachers in some parts of the state were able to begin carrying firearms as of Tuesday, had they volunteered to do so and undergone screening and training with a local sheriff's office.

Because the teachers must carry their guns anonymously, it is unclear how many may have chosen to bring a weapon to class this week.

“Everybody wants to know ‘How do we prevent it?’ How can we stop it. We don’t look at it as we want more guns, we look at it as we want more protection,” Bill Husfelt, a school superintendent in Bay County, told CBS News.

Florida shooting – in pictures Show all 10 1 /10 Florida shooting – in pictures Florida shooting – in pictures Police arrest a suspect in connection with the shooting at the Marjory Stoneman Douglas High School in Parkland, Florida Reuters Florida shooting – in pictures Parents wait for news after reports of a shooting at Marjory Stoneman Douglas High School in Parkland, Florida AP Florida shooting – in pictures Anxious family members wait for news of students AP Photo/Wilfredo Lee Florida shooting – in pictures Students being evacuated from the school AP Florida shooting – in pictures Students being evacuated from the school Getty Florida shooting – in pictures People gather waiting for word from students AP Florida shooting – in pictures Parents waiting for news on their children AP Florida shooting – in pictures People gather at a hotel where students were taken after the shooting Getty Florida shooting – in pictures Florida Governor Rick Scott speaks to the media as he visits Marjory Stoneman Douglas High School following the shooting AFP/Getty Florida shooting – in pictures Dr. Igor Nichiporenko, Medical Director Trauma, left, and Dr. Evan Boyer, Medical Director, Emergency Services, speak about treating victims and the suspect at a press conference outside Broward Health North hospital AP

Bay County is located in the Florida Panhandle, and is among a handful of smaller school districts to opt into the programme. Schools in Miami-Dade County and Orlando — the state’s two largest districts — have decided not to participate.

The new policies are the latest reforms to come in the aftermath of the shooting at Marjory Stoneman Douglas High School, including placing armed officers in schools to fight back in the case of a future emergency. Funding for those officers was paid for in part through a voter-approved tax hike last year.

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Florida is known for its gun-friendly state house, and the National Rifle Association has historically had a strong hold on state politicians who might push for gun control measures.

The new measure is not without its critics, including some who disagree with the policy who lost family in the Parkland shooting. Those critics argue that teachers should not face an extra burden, and should not have to worry about wielding a firearm while teaching children.