An explosion at an Ohio oil refinery blew out windows at homes in Lima on Saturday and could be felt at least 10 miles away, but it resulted in no injuries, police said.

All workers were accounted for after the blast at the Husky Lima Refinery, according to police.

The blast triggered a fire that burned into mid-afternoon and sent black smoke billowing into the air above the refinery. Crews were monitoring the air to make sure there was no danger to those nearby.

Those tests had not detected anything hazardous in the first hours after the explosion, said Heidi Griesmer, a spokeswoman for the Environmental Protection Agency.

The 6 a.m. explosion sparked a fire that raged for hours before it was contained 12 hours later, said Sgt. Andy Green of the Lima Police Department. The refinery's in-house firefighting crew expected to work through the night to completely extinguish it, Green said.

No one had to be evacuated, but nearby streets were closed for about seven hours and about 20 homeowners reported that the explosion broke their windows, he said.

"It was felt throughout the city," Green said.

It was too early to determine the extent of the damage or say how the fire will affect production at the plant in the coming days, said Husky Energy spokesman Mel Duvall.

The explosion happened in a processing unit where crude oil is heated to begin the process of breaking it down into other products.

The refinery anchors an industrial area in Lima, which is about 80 miles northwest of Columbus.