MELISSA (1080 KRLD) – One Collin County school district is warning visitors that members of their staff are ‘packing heat.’

Signs that staff members “are armed and trained” have started popping up at the entrances and exits of Melissa schools this week. The policy that allows staffers to carry a gun on campus has been around since 2016.

READ MORE: 19-Year-Old Tello Hernandez Faces Intoxication Manslaughter Charge Following Fatal Crash 

Any staff member in Melissa Independent School District can request to carry a firearm on campus, but must have a concealed handgun license and complete an “extensive active shooter training.”

READ MORE: Homeowner Terry Duane Turner Charged In Slaying Of Motorist Adil Dghoughi In His Driveway

Official say they then must then be vetted by Melissa ISD Police and Administration and approved by the school board.

Anyone who is approved by the School Board must place their gun in a secure and locked gun case, and must continue training.

MORE NEWS: Dallas Neighborhood Crime Spike Has Many Questioning, 'Is Uptown Going Downhill?'

The district doesn’t make the names of those that carry public, so parents do not know if their child is in a classroom with a gun.