OTTAWA — The tab for cleaning up military sites tainted by everything from asbestos to toxic chemicals and dud bombs and shells will come to at least $450 million over the next decade.

And although not all this money will come from the Defence budget, the estimate also doesn't count a number of problems still being studied. The contaminated sites are scattered across the country, from Goose Bay in Newfoundland and Labrador, to Valcartier, Que., and the British Columbia interior. As well, there are a number of offshore sites where Second World War ammunition stocks and even chemical weapons were dumped at sea long before the era of environmental awareness.

Many of the problems stem from decades of neglect, or date back to a time when little thought was given to long-term environmental consequences.

Briefing notes for Gordon O'Connor, the new defence minister, obtained through the Access to Information Act, say the military has already recorded environmental liabilities totalling $447 million.

They say environmental problems are a growing concern.

"The convergence of issues related to environmental contamination, past practices in the usage, handling and storage of hazardous materials and their impact on human health is a growing pressure for the department and for the government as a whole," the papers say.

The documents also say that Defence - with its thousands of buildings, vehicles, planes and other equipment - is the federal government's largest single producer of greenhouse gases. This adds another troubling challenge because while the government has pledged to cut greenhouse gases, the military is expanding and adding new people and equipment.

Cleanup problems include an estimated $100 million project at Goose Bay, where old-fashioned methods of handling fuel and wastes have caught up with the air force.

It will take at least 12 years to finish that job.

There are problems at Valcartier, north of Quebec City, where a cleaning and degreasing solvent used for years has been leaching into water both on and off the bases. Some private wells in the adjacent municipality of Shannon were found to be contaminated with the solvent and the military paid to connect the affected homes to the base water supply and to locate a new water source for the community.

Studies are still going on over the use of herbicides at CFB Gagetown in New Brunswick, including the notorious American defoliant Agent Orange, which was tested there in 1966 and 1967.

"The fact-finding approach to the herbicide spray program at CFB Gagetown is anticipated to be complete by the spring of 2007," say the documents.

A longer-term study is looking at herbicide use at other bases across the country.

There are continuing problems associated with the long-abandoned Mid-Canada Line, a string of 1950s-era radar stations that stretched from Dawson Creek, B.C., to nothern Labrador.

The sites were abandoned in the 1960s. Some of the decaying buildings are insulated with asbestos and coated with paint laced with lead and PCBs. Half-empty fuel barrels and rusting vehicles litter some of the stations.

For years, Defence argued that it had handled the sites according to the standards of the mid-1960s and that was enough. Now it is negotiating with provinces and native groups over meeting more stringent standards.

Projects are working on both coasts to evaluate sites where munitions were dumped. Some areas have already been marked on marine charts as danger areas.

Some of these sites may have to be cleaned up if they pose serious risks to human health and the environment. The notes have no estimate for the cost of these efforts.