09/24/2014 03:24 EDT | Updated 11/24/2014 05:59 EST

Rollover closes eastbound Highway 401 lanes in Milton

A tractor-trailer rollover has shut down the eastbound lanes of Highway 401 in Milton, Ont.

The Ontario Provincial Police say the eastbound side of the highway is closed at James Snow Parkway, along with the associated on-ramps.

The tractor-trailer was reportedly carrying gravel, which now has to be cleaned up.

The cleanup is expected to take about four hours.

The westbound lanes of the highway remain open.