WINFIELD — Milk sloshing inside a trailer may have caused a tanker truck to overturn Monday, dumping several thousand gallons of milk into a drainage ditch on County Line Road near Route 15.

About $12,000 worth of milk spilled in the accident, based on retail prices set by the Pennsylvania Milk Marketing Board.

George W. Adams, 55, of Dillsburg, driver of the rig owned by Harrisburg Dairies, said he was making the turn from Route 15 onto County Line Road at 12:48 p.m. when his rig upset.

“It was in very, very slow motion,” said Adams, as he watched crews from Northridge Group and Keller’s Towing work to right his truck. “The guy behind me couldn’t believe it was happening.”

Adams had a large brush burn on his neck, caused by his seat belt, but was otherwise uninjured. He said he was coming around the turn at about 10 mph when he felt a lurch as the milk sloshed inside the trailer, and then the rig upset.

“Thank God I was wearing my seat belt,” he said, staring at the crumpled cab of his 2001 Mack tractor.

He was able to unlatch his seat belt and open the door of the rig and climb out unaided.

When the truck upset, the hatches on the top of the tank opened, and several thousand gallons of milk spilled into a drainage ditch directly beneath the trailer. Adams said he had about 5,600 gallons of milk in the trailer, and officials at the scene estimated as many as 4,000 gallons spilled.

A Department of Environmental Protection official said the spilled milk posed no hazard and no absorbent materials or booms would be deployed. The milk will simply dilute with water as it flows toward the river, he said.

Northridge workers pumped diesel fuel out of the truck’s twin fuel tanks and spread absorbent materials on the pavement to soak up spilled fuel and oil. Then Keller’s Towing used two wreckers to roll the rig back onto its wheels.

County Line Road was closed between Route 15 and Park Road for about two hours while the rig was righted.