The Yukon government says contamination from an almost decade-old fuel spill at the former F.H. Collins Secondary School is worse than initially thought.

During soil remediation at the site of the old high school in Riverdale, contractors discovered that contamination from spills of heating oil in 2008 and 2009 is greater than expected, including the contamination of groundwater.

The government was made aware of the issue on June 14.

“We continue to assess the situation and are working to ensure that contaminated material does not migrate into the aquifer that supplies the City of Whitehorse drinking water,” Environment Yukon spokesperson Roxanne Stasyszyn said during a press conference held Wednesday afternoon.

“It’s important to note that we do not have evidence that hydrocarbons that are present in the soil and groundwater have reached the aquifer.”

Peter O’Blenes is the city’s director of infrastructure and operations.

He said there is a very minor risk that contamination will affect the aquifer because it is moving away from the wells.

“From a city standpoint, we’re very confident that this is a low risk,” O’Blenes said.

The city is currently waiting on results from water samples taken from two of the wells adjacent to the site.

The contaminated groundwater is located about 400 metres from the aquifer.

The shallow water table is 6.5 metres deep while the aquifer is at a depth of 22 to 44 metres.

Dr. Brendan Hanley, Yukon’s Chief Medical Officer of Health, said that even with contamination, the health risks are low.

“When fuel or petroleum hydrocarbons are absorbed by mouth and swallowed, the liver is actually very efficient at mopping it up,” he explained.

“That means you would actually have to drink several ounces of fuel in order to get a toxic effect.”

He added that hydrocarbons in water are easily detectable through taste and smell.

The government says it is removing all contaminated soil and will continue to monitor groundwater in the effected area.

“The first priority is to remove contaminated soil because that acts as a source for contamination in the groundwater,” said Amanda Janssens, the manager of the Site Assessment and Remediation Unit.

It was originally estimated that only 100 cubic metres of contaminated soil would have to be removed from the area.

As of noon Wednesday, that amount had tripled, and officials are continuing to chase the contamination.

As soil is removed, it is de-watered, or water that collects at the base of the excavation is pumped off.

“It’s very difficult to remediate groundwater,” noted Janssens.

“It’s oil, and it doesn’t want to go into the water, it wants to to stick to the soil; it actually absorbs to the soil particles.”

She said all of the water and soil that is removed will be sent to a permanent treatment facility for remediation.

Once the soil remediation is completed, they will install groundwater monitoring wells to make sure that the aquifer is not impacted.

Soil removal from the site is expected to take another three or four weeks, with monitoring wells installed by the end of the season.

The government could not confirm how the remediation work will affect the total cost for the F.H. Collins demolition project, but says it is not expected to be a significant increase.

Earlier this month, it was revealed that it would cost more than double an initial estimate due to higher than expected asbestos levels.

A 2011 rough estimated costs for demolition and hazardous material abatement at $2.5 million. The project is now expected to cost $6.9 million.

The spills were located at the building’s oil-fired heating system and underground fuel tank.

In 2008 and 2009, it was considered a small leak and all accessible oil was removed from the site with plans to remove further oil during demolition.

An old system that was installed in the 1960s, lines running underneath the foundation developed small pinholes – which allowed the fuel spill to spread.

The two underground oil tanks were also removed at the time and an above-ground tank was installed.

Underground oil tanks in government-owned buildings continue to be removed and replaced with lower risk systems.

Over the last couple of years, 15 tanks have already been removed.

Four more are scheduled for removal this year with an additional two to be removed in the upcoming years.

As well, the City of Whitehorse has been campaigning to educate residents about the potential risks of these tanks.

A city bylaw addressing these concerns is expected to come forward sometime in the new year.

The old F.H. Collins Secondary School opened in 1963 and gave way to its new successor in January 2016.