Yarmouth emergency workers evacuated the area around the Interstate 295 Park and Ride lot after a white substance was found leaking from a tanker truck only to discover the suspicious liquid was milk.

The Yarmouth Fire Department described the incident on its Facebook page Thursday.

After someone reported the substance, police established a perimeter to control access and evacuated the area.

Firefighters “conducted an assessment” and determined the substance, which was spilling out of the tank onto the ground, was milk. The carrier cleaned up the spill under the watchful oversight of the Department of Environmental Protection, the department said.

The milk spilled because the tank had been overfilled and then built up pressure overnight while the truck was parked there, the Fire Department said.