Most Smithfield residents lost power for more than three hours Friday morning.

A transformer exploded at an electric substation at about 8:30 a.m., sparking a fire and causing residents to lose power until about 11:30 a.m.

City Manager Pete Connet said both the Smithfield substation and a Progress Energy substation next to it were automatically shut off.

Workers cleaned up the spilled oil and made repairs at the substation.

Two accidents were reported in downtown Smithfield; one at the intersection of E. Market Street and S. Fourth and another at E. Market Street and Front Street. Officers did not know if the crashes happened because traffic lights were out.

Three employees were working in the substation at the time of the incident and were splashed by mineral oil from the blown transformer, but they were not injured, Connet said.

Connet said he does not know what caused the transformer to blow, but said there were problems before.

"It was a circuit that we had problems with about a month ago and they were doing some repair work to it to get it back on," he said.

The substation is down the road from the Smithfield Water Treatment plant. Original reports from Johnston Communications reported an explosion occurred at the water treatment facility.