An oil spill at the north end of State College shut down roadways for most of yesterday, causing detours and backups on Route 322.

The Nittany Oil Company truck left a 3.7-mile trail of diesel fuel from Waddle Road to Skytop Mountain. Lynn Woods, assistant maintenance manager for the Pennsylvania Department of Transportation (PennDOT), said limestone sand was put down to absorb the oil. It took most of the day for the material to soak up the fuel.

The spill occurred at about 5 a.m., but the Route 322 westbound exit ramp was not re-opened until 5:30 p.m.

"I've been with PennDOT for 20 years, and this is the biggest spill I've seen around here," Woods said.

Woods said that despite the massive amount of oil that was lost, the spill was less damaging to the environment because it occurred on a roadway where it was not absorbed into soil or water.

"There was a little runoff around Skytop Mountain, but maintenance took care of that," Woods said.

PennDOT equipment operator Doug Letterman said westbound traffic on Route 322 was redirected past Toftrees to Route 550.

"Of course there are angry people that are stuck in traffic, but we're trying to clean it up as fast as we can," Letterman said.

Both Letterman and Woods said there is no fire hazard caused by the spill because a biodegradable anti-skid substance was put down after the limestone sand was removed and brought to a hazard material waste facility.

"The anti-skid substance has the consistency of kitty litter, so it can be left on the roadway," Woods said.

Woods said crews would return to the scene sometime today to check for surface bleeding -- or absorbed fuel seeping out of the roadway -- and to put down more oil absorber if necessary. They will also check for damage to the asphalt, but expect no damage to the road surface.

PennDOT officials could not be reached for comment on the cost of the cleanup or any future ramifications of the accident.