MILTON, Wis. -

Authorities have reopened State Highway 59 east on Milton after a tanker truck filled with ethanol overturned Tuesday morning, spilling ethanol on the highway.

The roadway reopened shortly after midnight Wednesday, according to the Milton Police Department.

The Milton Police Department said the truck and trailer overturned at about 9:45 a.m. on Highway 59, approximately one mile east of Highway 26. The semitruck was eastbound on Highway 59 and overturned while driving through a roundabout.

Jim Blumer, an employee of Hammil Farm Center in Milton, said the nearby store wasn't evacuated but police stopped by to let him know about the spill.

"I heard some sirens this morning and a customer said, 'You've got to come and look at this.' So we went out the back and saw the truck on its side," Blumer said.

Milton police said officials at the scene determined the safest course of action was to allow the ethanol to leak out naturally rather than trying to offload it onto another tanker, which could create a fire hazard.

Police said the ethanol is draining into a retention pond adjacent to the crash site.

It was estimated there were approximately 8,000 gallons of ethanol on board, and it is draining in excess of 10 gallons per minute, Milton police said.

Conger said the Wisconsin Department of Natural Resources was at the scene to assist with the environmental impact assessment. At the time, he said it didn’t appear the spill would affect water in the area.

Police said the driver wasn't injured in the crash.

"We don't have any indication it was reckless driving or it was speed or anything like that. Witnesses said he was traveling at a normal rate of speed, something just happened that it overturned," Conger said.

Several nearby residents who were evacuated and were later allowed back into their homes.

The Wisconsin State Patrol is investigating the incident.