A 17-year-old student is facing charges after his loaded gun fell onto the gym floor at a Prince George’s County, Maryland, alternative school on Thursday morning, police said.

It happened at Non-Traditional Program 9-12 South school in Cheltenham, Prince George’s County police said.

A “ghost gun”— a gun without a serial number — fell out of the teenage boy’s waistband in the gym at around 9:15 a.m., police said.

The 9th grade student is being charged with having a handgun, having a dangerous weapon on school property, possession of a firearm by a minor and having a loaded handgun.

Run by Prince George’s County Public Schools, the alternative school is designed for students in 9th through 12th grades, according to its website. It used to be known as Croom Vocational.