Some Florida teachers will be able to carry firearms in the classroom starting Tuesday, the result of a hotly debated law that was approved by the Florida Legislature in May.

The law, which gives school districts the option to arm teachers, as well as security guards, was passed in response to the 2018 shooting at Marjory Stoneman Douglas High School in Parkland, Fla., which left 17 people dead. Teachers will be allowed to carry guns via the Guardian Program, which was created in the wake of the shooting.

Currently 39 counties participate in the program, according to the Florida Department of Education. But not all school districts agree that teachers should be armed. According to The Miami Herald in September, only 11 school districts had sought to arm teachers through the program. Florida also does not track how many of its teachers are carrying weapons, The Herald said.

The program was established in 2018 as part of the Marjory Stoneman Douglas High School Public Safety Act, a Florida bill passed to address gun violence on school campuses. Then, it was the recommendation of legislators that certain employees be allowed to carry guns on campus so they could immediately respond to a school shooting. Educators who served solely as teachers were excluded.