Police on Tuesday morning arrested a 17-year-old junior at Antioch High School after he admitted to setting off a chemical reaction explosion in a restroom at the school on Monday.
Metro police spokesperson Don Aaron said the device exploded in a first floor boy's bathroom around 9 a.m.
A faculty member was close to the explosion but was not injured.
No students were in the restroom at the time of the explosion and no other devices were found, Aaron said.
Metro Schools' spokesperson Olivia Brown said the school was on lockdown immediately following the explosion. The lockdown was lifted about two hours later.
Brown said the bathroom was not significantly damaged.
The teen was identified as a possible suspect and interviewed.
During the interview, police he confessed to putting reactive chemicals into a plastic water bottle and placing it in the restroom.
He said he did so as a prank.
Police said the teen would be charged as a juvenile with possession of a prohibited weapon.