Detroit — Two city workers became the butt of a joke gone bad when they went to use the restroom and the toilets exploded.

Police are investigating after a firecracker left taped to the lid of a toilet went off at about 8:50 a.m. Wednesday in the 1000 block of Erskine near the city's Eastern Market district.

When the lid was lifted, it triggered the explosion, police said.

Media reports indicated the location as the Detroit Fire Department's apparatus and repair garage. Fire officials referred all questions to the police.

The men, ages 41 and 59, were both taken to the hospital for treatment of minor injuries, police said.

The bomb squad was called in to check out the restroom and cleared the building.

No suspects have been identified, so the prankster(s) remain at large.

cramirez@detroitnews.com

Twitter: @CharlesERamirez