A truck delivering diesel in Fernie has leaked fuel into the Annex pond in Fernie.
Shawn Ivany, Fernie Fire Chief, said the Ministry of Environment are currently at the scene attempting to clean up the spill, and prevent it from reaching the river.
He said the spill happened at around 2 p.m. Wednesday, when a tanker was delivering diesel to the Fernie Cardlock.
A woman walking her dog in the area noticed the diesel on the pond and called Fernie Fire Rescue.
"There was a diesel spill that got into the storm drains and rain flushed it into the Annex pond," said Ivany.
"We believe it came from a tanker making a delivery to the Cardlock."
Gary Tomlinson, owner of Cardlock, said the driver was completing a delivery of fuel and forgot to put the cap on the hose.
"He was rolling up the hose and dropped the end and had not put the cap on it so fuel came out.
"It was raining heavily and diesel floats on water, so it was washed into the drains."
Fernie Fire Rescue responded to the site and started work to prevent the spill spreading.
"We put down booms on the water to prevent it spreading into the water, and we put down sand to try to stop it getting into the river but we don't know if any would have got in," said Ivany.
"We contacted the Ministry of Environment in Cranbrook and Environment Canada and they determined that a clean up was necessary so a clean up contractor came and took away around 4,000 litres of contaminated water to remove the affluent."
The contractor attempted to flush the storm drains and skim the diesel off the surface of the water.
Ivany said it is not possible to estimate how much diesel was spilled, but it is likely some would still be left behind.
"It's not possible to get it all out," he said. "It will have soaked into the vegetation and will come out over time.
"The Ministry of Environment are still on site following up and will be handling an investigation into what happened," he said. "The company delivering the diesel did not report any spill."
Tomlinson said he believed the spill to be around 20 litres and that it is not necessary to report spills less than 100 litres.
"We are going to upgrade our cameras and ensure that in future drivers are trained in our procedures," he said. "We are sick to our stomachs that this happened. Spilling fuel into a duck pond is bad, however small it is, and it reflects poorly on us as a business.
"This has been our worst week in a long time."