Heating oil leaking into the Yukon River was noticed Monday after a complaint was received of fuel and water flowing along a downtown alley, says a government spokesman.

Dennis Senger of the Department of Environment said today a boom was placed on the river to capture what he described as a minor sheen flowing out of the Strickland Street storm drain.

The boom remains in place today, with just a faint trace of oil products visible.

The RCMP detachment was notified of the fuel oil running down the alley by an anonymous caller at 11 a.m. Monday. Police then contacted the oil spill line, Senger said.

He said an unknown volume of oil had originated from an underground tank buried in the alleyway between Third and Second avenues.

The tank is attached to an older and vacant Third Avenue building next to Super Valu, and across the alley from the NAPA Auto Parts building.

The combination of oil and water from heavy rainfall was flowing into the storm drain running along Third, Senger said.

The Whitehorse Fire Department was called in to assist with the initial containment and cleanup of the surface residue, and the storm sewer catchments were pumped out into containers by city staff.

Senger said the owner of the building, Klaas Heynen, has contracted EBA Engineering to oversee the site investigation and removal of the tank, as well as Arctic Backhoe to do the digging.

'We also received information from the owner's son that the building has not been used for 20 years, nor has the tank.'

It appears at some point in the past the filler spout had either been broken off at ground level, or had been placed at ground level originally, and the filler cap was faulty or somehow had been removed, he said.

Senger said it's believed the tank began filling up with precipitation over time and overflowed in recent days because of the heavy rainfall.

Once the tank is removed, department officials will have a clearer picturer, he said.

There is nothing, he added, to suggest vandalism or anything untoward that may have led to the leaking fuel.

Senger said officials do not suspect any underground leaking from the tank, as evidence would have likely appeared in the city's storm sewer system prior to Monday.

The removal of the tank has been complicated by the presence of three or four large electrical conduits running directly beside the tank, if not slightly over top.

Senger said Yukon Electrical Co. Ltd. has rerouted the power. It was his understanding this morning that Yukon Electrical and Arctic Backhoe were discussing the tank's removal.