Marwell Tar Pit:
A historical chronology of the site
Based on “Marwell Industrial Area: Historical Research Project” prepared by
Midnight Arts for the Government of Yukon and City of Whitehorse (April 1999)
1940s
The United States Corp of Engineers contracted Standard Oil of
California to construct and operate a petroleum refinery (the
‘Refinery’) in the immediate vicinity of what is now the Marwell Tar
Pit contaminated site in order to process crude oil extracted and
transported from Norman Wells, NWT. The Refinery operated
during 1944 and 1945, after which time it was shut down and
arrangements made by the Government of the United States of
America for its sale.
1946
An aerial photo of the area taken this year does not show the
Marwell Tar Pit – it did not yet exist. Instead, in the same location,
the photo shows an 80,000 bbl petroleum hydrocarbon storage tank
surrounded by a retaining berm. (Remains of this berm are still
visible at the tar pit site.)
1947
The Refinery and all its contents (but not the leased land) was
purchased by Imperial Oil Ltd., who then dismantled the refinery
and moved it to Alberta. Historical information indicates that
although some initial work was conducted at the Refinery to halt
operations and ‘mothball’ the facility, hydrocarbon product and
waste continued to be located at the Refinery when the dismantling
activities commenced.
1952
An aerial photo of the area taken this year shows that many of the
Refinery components, such as the storage fuel tanks and buildings,
had been removed. The Marwell Tar Pit is now clearly visible in this
photo as a black pool of liquid. Therefore the tar pit was created
sometime between 1946 and 1952.
1958
A man walking through the Marwell Tar Pit became trapped in the
semi-liquid tars present and died of exposure. The coroner’s jury
‘strongly recommend that the oil pool, which has proven to be a
hazard to life, be removed by whatever means necessary as soon
as possible.’
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1958 to
Following this fatality (the only documented death at a
early 1960s contaminated site in Canada) the Marwell Tar Pit was fenced.
Considerable correspondence occurred between the Office of the
Territorial Commissioner, the Department of National Defense and
the Department of Northern Affairs and National Resources as to
who was responsible for addressing this hazard.
1960s
Precise dates are not available but correspondence from this time
indicates that some attempts appear to have been made to drain
water out of the pit and cover up the remaining oil and
contaminated soil. Air photos from this period show that the extent
of exposed liquid has decreased.
1970
The land where the Marwell Tarp Pit is located was transferred to
the Government of Yukon from the Government of Canada as part
of a large Block Land Transfer. Prior to and during WWII, the
refinery site was comprised of one privately held lot and the
remainder Crown land.
1989
Environment Canada staff conducted a site investigation of the
Marwell Tar Pit and collected water and soil samples from the pit
and adjacent creek. Contamination from the tar pit was migrating in
the direction of the creek, which flows into the Yukon River, but had
not yet reached the creek. Soil in and near the pit was
contaminated with a mixture of petroleum hydrocarbons. It was
noted that “oil and grease” are considered a deleterious substance
under the Fisheries Act and that the Marwell Tarp Pit should be
cleaned up in order to prevent the creek and groundwater from
becoming contaminated.
1990-92
A Phase I Environmental Site Assessment (ESA) and a partial
Phase II ESA were carried out by Piteau Engineering, under the
auspices of a joint federal-territorial working group and funded
through the Arctic Environmental Strategy. Contamination was
found to extend under Jasper Road to the south of the site as well
as to the northeast in the direction of the creek. Should
contamination reach adjacent occupied properties (to the south) or
reach the creek (to the northwest) the potential for impacts to both
human health and the environment will greatly increase. Both Soil
and groundwater are contaminated. The total volume of
contaminated material was estimated at 27,000 cubic metres.
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1993-94
Pilot studies of both a biological treatment process and a thermal
desorption process for the remediation of the contaminated soil at
the Marwell Tar Pit were undertaken during this time, and were also
sponsored through the joint federal-territorial working group. Both
processes were deemed to be viable for the site but various
additional testing and refinement would be required for either
process to be fully successful at the site. Estimated costs for the
full-scale application of either of these remediation process were
$3-4 million (1993-4 dollars). No action was taken to implement
either process for full-scale remediation of the site.
1994-99
Beginning in 1994, a number of letters were exchanged between
the governments of Yukon and Canada regarding the extent of
contamination at the Marwell Tar Pit and the need for remedial
action to be undertaken.
1997
Routine monitoring of the surface flow of heavy tar-like substances
by the Yukon Department of Renewable Resources was
undertaken in the late 1990s. Staff marked the known extent of
contamination with pegs and then documented the movement of
the tar-like substances over time. In 1997, this monitoring showed
that the tar-like substances were seeping out of the bank of the
creek northeast of the Marwell Tar Pit. The Yukon government
excavated a 1-metre deep by 30-metre long interceptor trench
parallel to the creek between the creek and the tar pit. A cross
section of the tar plume could be seen along the interceptor trench
wall. It did not appear that the plume had reached the creek. The
interceptor trench has subsequently been effective as an interim
measure to prevent contamination of the creek.
1998
On May 4, the Marwell Tar Pit was declared a Designated
Contaminated Site pursuant to s.114 of the Environment Act and
the Contaminated Sites Regulation.
1999
The Yukon Department of Renewable Resources commissioned
historical research into the entire Marwell Industrial area (including
the tarp pit) to locate contamination in the area, and to determine
who was in charge of the contaminants at the time they were
released. Research found that responsible parties include the
Canadian Department of Defence, the US Government, W.M
Barnes, and Imperial Oil Ltd.
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2004
Discussions about remediating the tar pits resumed when the
federal government indicated it would be receptive to a Yukon
government proposal for assessment and remediation.
Environment Yukon submitted a preliminary proposal to Indian and
Northern Affairs Canada which determined that it would be willing
to consider the tar pit site under a newly-developed “shared
responsibility” program for contaminated sites.
2006
Environment Yukon, together with the Ta’an Kwäch’än Council
submitted a proposal to the Northern Strategy Trust for the
assessment and remediation of the tar pit. The proposal was
approved in the amount of $1.995 million.
2007
Negotiations began between the governments of Yukon and
Canada
2010
The Government of Canada and the Government of Yukon
conclude an agreement for funding the remediation of the Marwell
Tar Pit site.
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