Millions of litres of harmful contaminants — including sewage and jet fuel — have been spilled across great swaths of Canada's pristine Arctic in recent years, an analysis by The Canadian Press has found.

A classified government database reveals the alarming extent to which Canada's North has been an accidental dumping ground for dangerous liquids.

This never-before released information comes to light as the Harper government reviews its Arctic environmental-protection rules in the wake of a catastrophic oil spill in the Gulf of Mexico.

The Arctic spills to date have been smaller than the giant BP disaster off the U.S. coast, but are a reminder of the continuing threat from development to one of Canada's most vulnerable ecosystems.

The information has been kept in an environmental-enforcement database called NEMISIS. The acronym stands for National Enforcement Management Information System and Intelligence System. Federal enforcement officers use the database to track and prosecute polluters and environmental lawbreakers.

It took The Canadian Press two years and a complaint to the information commissioner to pry the data from Environment Canada under the Access to Information Act.

The news agency then created its own spills database using the government information, which covers the period from January 2004 to last November.

The analysis found 260 spills in the North over five years. There were 137 spills in the Northwest Territories, 82 in Nunavut and 41 in the Yukon.

Some spills took weeks or even months to clean up, while others were dealt with in a day or less.

In one case, an unspecified amount of diesel seeped from a container in the Yukon for 2,013 days — more than five years — before someone finally plugged the leak.

Other significant spills in Canada's Arctic:

  • Four million litres of silt water was discharged when equipment failed at a Diavik Diamond Mines plant in the Northwest Territories in May 2008. Environment Canada says there weren't any chemicals in the water.
  • Another Diavik Diamond Mines spill last May in which 500,000 litres of an unknown substance leaked from a pipeline in Yellowknife.
  • 300,000 litres of sewage that flowed out of a sewer pipe in Inuvik, N.W.T., in February 2008.
  • Another 250,000 litres of sewage that leaked from a municipal sewage-treatment plant in Tungsten, N.W.T., in February 2006.
  • A sewer overflow in Rankin Inlet, Nunavut, in April 2007 that released 600,000 litres.
  • Another sewer overflow in Watson Lake, Yukon, in February 2006 that dumped 250,000 litres of sewage into the Flat River. The North American Tungsten Corp. was blamed for the spill. Spill samples taken by the company "indicated the spill was not deleterious to fish," Environment Canada said.
  • 150,000 litres of jet fuel that seeped from a container in Iqaluit in April 2007. The spill is blamed on Nasittuq Corp., which maintains northern radar sites for the Defence Department. An identical entry appears for the Defence Department. Environment Canada says these two incidents are one and the same.

There are many instances in which the database doesn't say how much time it took to clean up the mess.

Indeed, the government's tracking system is riddled with blank entries. Often it doesn't say how much of a contaminant has been spilled. Sometimes even the name of the responsible party isn't known.

The head of Environment Canada's environmental enforcement branch, Manon Bombardier, said her staff enters information into the NEMISIS database, often after speaking to provincial officials.

Sometimes information that doesn't fall within Environment Canada's mandate might not be entered into the database, she said by way of explanation for the blank entries. Bombardier acknowledged there may be other reasons data are missing, but she didn't offer any. The department later followed up with an email saying NEMISIS "is often being improved and updated to manage its effectiveness."

Bombardier insisted the department can take action against environmental offenders even if some data is missing. "For those files that merit an enforcement action, you can be sure that the information is in NEMISIS," she said.

She added the department is just one of several that can prosecute and penalize rulebreakers. Others, including Indian and Northern Affairs and the provinces and territories, have different enforcement tools at their disposal.

Bombardier said Environment Canada generally relies on the federal Fisheries Act and the Canadian Environmental Protection Act to enforce environmental laws.

The government has prosecuted two companies in the North under the Fisheries Act since 2004, she said, and two warning letters have gone out.

"People feel that prosecution is the only way that enforcement takes action," Bombardier said. "We have other tools to apply, and it all depends on their circumstances."

The database lists 75 diesel spills across the North. That's followed by 28 sewage spills, 26 spills of unspecified or unknown contaminants and 25 jet-fuel spills.

World Wildlife Fund expresses concern

The number of northern spills shocked at least one environmental group.

"It begs the question of whether we've got a chronic problem of oversight related to toxic spills in the North," said Craig Stewart, director of the World Wildlife Fund's Arctic program.

"If there are so many repeat occurrences, what are the cumulative effects of these spills and why haven't we heard more about them up until now?"

Canada's federal oil and gas regulator is reviewing Arctic safety and environmental drilling requirements following the Gulf spill. The head of the National Energy Board wouldn't rule out a similar accident in the Arctic. "No safety regulator can possibly say that an accident will never happen," Gaetan Caron said recently.