Two Hydro Ottawa workers were taken to hospital in serious condition after an electrical panel exploded in an underground parking garage on Wednesday, according to the fire department.

It happened at 265 Poulin Ave., a highrise apartment building, at about 11:45 a.m. ET.

One of the workers, a 58-year-old man, suffered second-degree burns on his arms and first-degree burns on his face, paramedics said.

He was taken to hospital in serious condition.

A 26-year-old co-worker suffered first-degree burns on his face and possible internal injuries due to the force of the blast. He was taken to hospital in serious but stable condition, paramedics said.

Some residents chose to leave the building, said fire department spokesman Marc Messier. There was no mandatory evacuation.

It was a short blast caused by an electrical failure, and the fire was out when firefighters arrived.

There was heavy smoke throughout the parking garage, which was later being ventilated to allow hydro workers inside to assess the damage, Messier said.

Three buildings in the area were left without power after the blast.

OC Transpo and City Hall's office of emergency management are on standby. If power can't be restored in a timely fashion, Messier said the buildings without power may be evacuated.