Emergency crews have knocked down a fire following an explosion at a wastewater treatment plant in Pickering.

Firefighters were called to attend the fire at approximately 9:20 a.m. Tuesday morning.

At the time, thick, black smoke could be seen rising from a building at the Duffin Creek Water Pollution Control Plant, in aerial footage recorded by the CTV News chopper.

The Duffin Creek facility, located on McKay Road near the shore of Lake Ontario south of Highway 401 at Brock Road, is just east of the Pickering Nuclear Generating Station.

Durham Police spokesperson Sgt. Nancy van Rooy said all the wastewater plant's employees have been accounted for, and there are no reports of injuries.

Police also said they have closed Squires Beach and McKay Roads to traffic.

Investigators are looking into the possibility a buildup of methane gas touched off the explosion.

The facility is jointly owned and operated by Durham and York Regions.

According to the Durham Region website, the plant serves several communities including Aurora and Newmarket in the north, Vaughan in the west, as well as Richmond Hill, Markham, Pickering and Ajax.

Durham regions says the water supply has been unaffected.