MILTON, Wis. -

An ethanol tanker tipped over and spilled its load while negotiating a roundabout because of a shifting load, according to the driver’s statement to Milton police.

The crash occurred Nov. 27 and closed State Highway 59 east of Milton for nearly 24 hours. About 8,000 gallons of ethanol drained from the tanker.

The driver told Milton police he saw the rear axle of the trailer come off the ground. He said he tried to straighten the truck to correct, but the weight of the load pulled the truck over.

A witness told police she saw the right side of the trailer lift and tip over. She said the trailer tipped as it was negotiating the second part of the turn. She said the truck was never in the median.

According to the Department of Natural Resources, the 8,000 gallons of ethanol slowly leaked into a retention pond.

It's no secret many Rock County residents aren't big fans of roundabouts.

"I think there's too many. I don't mind them but not when there are several in a row," said Milton resident Wendy Ritacco.

"Around here, there's not much traffic, and they seem to be more confusing than anything" said Rock County resident Greg Coyle.

In a statement, Wisconsin Department of Transportation spokesman Michael Bie said, "The DOT designed the roundabouts in the area to ensure they could safely accommodate the freight traffic associated with the ethanol plant, and they were built to those standards."

"It was a direct line to this settling pond, this retention pond. The pond itself is contained. It's not connected to any ground water supplies," said Robert Manwell, DNR regional public affairs manager.

Manwell said the owner of the trucking company will continue to monitor the pond.

"(We'll) monitor the water in the pond a couple of times a week for a month so that we can tell if the ethanol is dispersing and degrading naturally as we expect it will," Manwell said.

Drivers in the area aren't surprised that roundabouts may have contributed to the crash.

"I've never seen anybody having trouble, but I've never been behind a big rig like that, either, so I couldn't speak for them," Ritacco said.

"You can look at it and see where the trucks have jumped over the edges and are chewing it up already," Coyle said.

The driver of the tanker truck wasn't injured in the crash. The Wisconsin State Patrol is investigating the incident.