Two years and $200,000 later, the Yukon government is closing the book on its search for a fuel leak, which contaminated soil in parts of downtown Whitehorse.
Although the source of the leak remains a mystery, the level of pollutants has diminished to zero, so the government will stop collecting and treating fluids from the leak, said Brian Levia, manager of monitoring and inspections at Environment Yukon.
Tests for hydrocarbons and heavy metals in the water collected in the sump beneath the Optometrists Building, on the corner of Lambert and Second Avenue, came up clean, he added.
The leak was first discovered in late March 2005, after an oil sheen was reported on the Yukon River, directly east of Lambert Street.
Officials traced the fuel to the sump beneath the Optometrists Building where it was collected through a weeping-tile system.
Environment Yukon spent months probing and digging around the sump, combing through two years of fuel records and following up on public tips without striking the source.
In December 2005, staff noticed the amount of fuel in the sump was not increasing and the level of hydrocarbons was well below regulated maximums.
So they gave the order to stop treating the sump water in July, and the equipment was removed from the basement of the Optometrist Building in October.
The treatment system recovered a total 4,000 litres of fuel.
Environment Yukon staff will continue to investigate the mystery if any new information comes available.
Under territorial law the polluter pays for the clean up, but since no source has been found the territory has footed the bill.