OTTAWA - The Canadian navy is relaxing some pollution rules for warships plying Arctic waters after skippers warned their ships were at risk of becoming smelly garbage scows.

Instead of having to carry all waste food on deck for eventual disposal at port, the ships will be allowed to dump it at sea.

The changes "help alleviate our COs (commanding officers') concerns (with regard to) accumulated food remnants stored in garbage bags on decks during ever-increasing global warming summers,'' says an internal memo, obtained by The Canadian Press under the Access to Information Act.

"These food remnants may decay or putrefy and generate an occupational health and safety issue on board ships (that) our COs can ill afford while striving to enforce Canadian sovereignty in our internal Arctic waters.''

The revamped orders, expected this fall, would also allow Canadian ships to dump raw sewage offshore in the Arctic and even to toss garbage bags overboard if there are "operational'' reasons for doing so.

"If the above instructions and limits cannot be met for operational or safety reasons when at sea and the ship's holding capacity is about to be exceeded, then garbage shall be made negatively buoyant prior to discharge and released at the farthest practical point from land,'' says a proposed revision.

Military-source pollution in the sensitive Arctic environment is becoming a navy headache as the federal government sends more warships north on sovereignty patrols in a region already under assault from global warming.

"Any new flora, fauna or pollution in our Arctic internal waters carries a risk to adversely impact its embattled ecosystem, as the intensity of past climate limitations gradually decline due to escalating global warming,'' says a draft version of the new orders.

Reliably cold temperatures once helped naval commanders deal with the garbage problem through freezing, but warmer weather is changing protocols.

Now, the new orders will allow "moderate amounts'' of pulped-food waste -- once banned from disposal in the Arctic -- to be dumped if a ship is at least 12 nautical miles or about 22 kilometres from shore.

The orders will also allow raw, untreated sewage to be flushed into the sea at the same minimum distance and, to help dispersal, only while the ship is moving at a moderate clip.

Previously, the navy banned the disposal of raw sewage in Arctic waters but the new orders will reflect the more relaxed provisions of the Arctic Water Pollution Prevention Act.

Submarines, which have highly limited storage capacity for waste, are being given even more leeway, including a provision allowing oily bilge water to be flushed directly into the ocean. However, all of Canada's four new Victoria-class subs are being equipped with technology that will remove oil from bilge water, making the problem moot.

All Canada's warships are technically exempt from the Canada Shipping Act as well as from other laws with environmental restrictions, although navy ships are legally bound to comply with ecosystem protections under the Fisheries Act.

However, senior brass have ordered that the fleet will nevertheless act as though all federal environmental legislation applied to navy operations, with exceptions for emergencies and operational restrictions.

The problem in the Arctic is that the only major port facility for offloading garbage and sewage is Iqaluit, and waste matter can overwhelm the storage capacity of ships during extended missions.

At the same time, Ottawa is ordering more ships north to bolster Canada's Arctic sovereignty claims. In August, for example, the 10-day Operation Nanook involved three navy vessels -- including a submarine, HMCS Corner Brook, the first time a Canadian sub has participated in such an operation.

Navy spokesman Cmdr. Jeff Agnew said the recent revisions to pollution-prevention orders simply reflect changes in civilian law, and allow ships' commanders more flexibility.

"Notwithstanding that we're less restrictive than we used to be, we are far more restrictive than the law requires us to be,'' he said in an interview. "It's good stewardship.''

Another spokesman noted the navy is in the Arctic partly to be able to react quickly to environmental disasters.

"One of the components of Operation Nanook was responding to an environmental crisis, and it's only by being up there that we're going to be able to respond to environmental crises caused by increased traffic in the region,'' said Lt. Jordan Holder.

A spokesman for the Sierra Club of Canada said the melting Arctic -- already under pressure -- can ill afford any more pollution.

"Having to take waste to a port to be properly disposed of is worth the inconvenience . . . rather than dumping it into our newly exposed ocean,'' said Jamie Kirkpatrick from Toronto.

"We're no longer in an era where you can say the solution to pollution is dilution.''