A burst pipeline gushed 2.5 million gallons (9.5 million liters) of toxic waste onto more than 4.5 million square feet (420,000 square meters) of wetlands wilderness, known as muskeg, in northern Alberta, Canada.

Controversy surrounds exactly when the leak started and how much the pipeline’s owner, Texas-based Apache Canada Ltd., knew about the spill.

Apache reported the spill to Canada’s Energy Resources Conservation Board on June 1, but estimates of the massive size of the spill weren’t publicly released until June 12, reported the Globe and Mail. That information came only after someone reported the spill to a local television station.

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On their website, Apache claims that the spill has been contained and that there is no danger to the public.

Members of the local First Nation, the Dene Tha’, don’t agree with Apache.

The Dene Tha’ expressed concern that the leak may have been going on for a long time before either official report, according to the Wall Street Journal, because of the extent of the dead and dying plants affected by the spill. A Dene Tha’ technician who surveyed the area on June 6 found that the spill had saturated the wetland. He also located spill material in a culvert outside of the containment area.

“Every plant and tree died” in the area touched by the spill, said James Ahnassay, chief of the Dene Tha’, in the Globe and Mail.

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The spill occurred less than 10 miles (16 kilometers) from the Dene Tha’ reserve. The Dene Tha’ depend on the fertility of the region’s ecosystem for hunting and fishing, so the spill threatens their way of life.

“We don’t believe that the government is doing enough to ensure upgrades and maintenance of the lines,” Ahnassay told the Globe and Mail.

Ahnassay’s concern may be justified considering that two other major spills have occurred in  the area in recent years. In late May of 2012, approximately 800,000 liters of an oil-water mixture spilled from a Pace Oil and Gas Ltd. Operation in northern Alberta, reported the Huffington Post. In September of the same year, nearly 3.5 million liters of oil gushed from a pipeline run by Plains Midstream Canada, according to the Canadian Broadcasting Corporation.

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