ST. PAUL — A Metro Transit police officer was hurt when an explosive device he was preparing for a training exercise went off.

The explosion happened Wednesday afternoon at a Metro Transit facility in St. Paul used for overhauling buses.

Metro Transmit spokesman Howie Padilla said the officer had an explosive that his police dog would search for. Padilla said the dog was still inside the squad car when the device exploded.

The seven-year veteran officer suffered non-life-threatening injuries. The St. Paul police bomb squad was called in as a precaution.

Neighboring businesses also were evacuated as a precaution. The explosion happened after bus employees had left for the day.