Calgary, AB., Dec. 7, 2007 (TSX – COS.UN) — Canadian Oil Sands Trust (the “Trust” or “Canadian Oil Sands” or “we”) today provided an update regarding the fire on the morning of December 5th at the Syncrude oil sands plant. The fire occurred in the environmental section of Coker 8-3 in an area called the electro-static precipitators (“ESP”). ESPs are used to knock out fine dust particles from the coker flue gas. The fire was extinguished in the early hours of December 5th. There were no injuries and the fire damage was limited to the ESP section of the unit.

Coker 8-3 continued to operate at reduced rates while investigations into the cause and required repairs were conducted. Safe operation of the coker unit was facilitated by bypassing the damaged ESP unit; however, provincial regulations limit the amount of time that the flue gas stream can remain in this bypass mode. Syncrude now believes that the length of time that will be required to make repairs to the ESP unit will be longer than the allowed bypass time. Consequently, Syncrude has decided to shutdown Coker 8-3 for approximately two to four weeks to make the necessary repairs. These repair procedures are now underway. Production from the rest of the facility is not expected to be affected.

On October 31, 2007 the Trust provided guidance of 111 million barrels for annual 2007 Syncrude production with a range of 108 to 114 million barrels. We expect the shutdown of Coker 8-3 will result in 2007 production still falling within the range of 110 to 111 million barrels. Any potential impact of this incident on 2008 production and costs will be addressed later in December when the Trust announces its 2008 budget.

Located near Fort McMurray, Alberta, Syncrude Canada operates large oil-sands mines and an upgrading facility that produces a light, sweet crude oil on behalf of its joint venture owners, which include Canadian Oil Sands Limited, ConocoPhillips Oilsands Partnership II, Imperial Oil Resources, Mocal Energy Limited, Murphy Oil Company Ltd., Nexen Oil Sands Partnership, and Petro-Canada Oil and Gas.

Canadian Oil Sands provides a pure investment opportunity in the Syncrude Project through its 36.74 per cent working interest. The Trust is an open-ended investment trust managed by Canadian Oil Sands Limited and has approximately 479.3 million units outstanding, trading on the Toronto Stock Exchange under the symbol COS.UN.

Advisory: in the interest of providing Canadian Oil Sands Trust (“Canadian Oil Sands” or the “Trust”) unitholders and potential investors with information regarding the Trust, including management’s assessment of the extent of damage or impact of the fire on Syncrude’s operations and any impact on the Trust. By their nature, forward-looking statements involve numerous assumptions, known and unknown risks and uncertainties, both general and specific, that contribute to the possibility that the predictions, forecasts, projections and other forward-looking statements will not occur. Although the Trust believes that the expectations represented by such forward-looking statements are reasonable, there can be no assurance that such expectations will prove to be correct. Some of the risks and other factors which could cause results to differ materially from those expressed in the forward-looking statements contained in this release include, but are not limited to: the expected time to complete repairs to the ESP unit and consequent duration of Coker 8-3 shutdown, the expected production in 2007, issues relating to the operation of complex operations such as upgrading of oil sands; labour and cost pressures in the oil sands industry and in the Fort McMurray area in particular; the regulatory changes that impact oil and gas operations; general economic, business and market conditions; commodity prices; and such other risks and uncertainties described from time to time in the reports and filings made with securities regulatory authorities by the Trust. You are cautioned that the foregoing list of important factors is not exhaustive. Furthermore, the forward-looking statements contained in this release are made as of the date of this release, and the Trust does not undertake any obligation to update publicly or to revise any of the included forward-looking statements, whether as a result of new information, future events or otherwise. The forward-looking statements contained in this release are expressly qualified by this cautionary statement. The information was approved by management on December 6, 2007 and circumstances after this date may change the outcomes or results achieved.

-30-
Canadian Oil Sands Limited
Trevor Roberts
Chief Operations Officer
(403) 218-6214

Units Listed – Symbol: COS.UN
Toronto Stock Exchange
For further information:

Ryan Kubik
Chief Financial Officer
(403) 218-6202
investor_relations@cos-trust.com

Web site: www.cos-trust.com