Residents in the area of the Bronte GO Station and Wyecroft Road received a bit of a scare Wednesday afternoon as an explosion broke the calm of the evening commute.

Employees of ROPAK Packaging, 2240 Wyecroft Rd., said the noise came from their building's transformer, which shorted out, forcing an evacuation of the building.

Police quickly arrived on the scene diverting traffic away from the area, while the Oakville Fire Department moved in and put out the ensuing fire.

"An electrical fire in the transformer room was what started this, but we don't know what started it," said Fire Chief Richard Boyes.

"It spread and breached the wall. It was contained to one small area of the plant, but we do have smoke throughout the plant and we're doing ventilation right now."

One employee reportedly twisted his ankle during the incident, but beyond that no injuries were reported.

Damage to the building has yet to be estimated.