SOMBA K'E/YELLOWKNIFE - Now that the spring thaw has begun, one Yellowknifer is urging his fellow homeowners to keep a close eye on their oil tanks.

Beware of oil tanks with small leaks, says Ron Kent, senior environmental engineer. Kent wants people to watch out for leaks as little as a couple of millimetres in diameter. - Elizabeth McMillan/NNSL photo Tips to avoid leaking oil tanks Your tank should be easily accessible and easily filled by the delivery person. He/she should not have to reach over his/her head to fill the tank. Your tank must have a operational whistle. Drain water and sludge from your tank once per year. Keep your tank free of snow and ice, and make sure that melting snow and ice will not fall on it. Walk past your tank regularly to inspect and smell it. In the spring, run your hand underneath your tank every day to see if it is leaking. Piping must have a flexible connection at the tank and should be continuous without hidden joints or connections and the filter should be next to an appliance.

"Check your tanks daily for the next three weeks," said Ron Kent, a senior environmental engineer with FSC Architects and Engineers.

Kent has been supervising oil spill cleanups for 35 years. He said his company has dealt with more than 60 spills in Yellowknife over the last two years.

"In the last five years it's been getting worse and worse," said Kent.

He said there are a number of factors contributing to the increase in spills.

Holes in oil tanks are caused by a combination of chemical and bacterial corrosion. One factor causing leaks is that sulphur is being removed from diesel fuel, making it less toxic to bacteria.

Another reason he stated was that insurance companies won't allow people to put their tanks inside their homes.

Kent said generally the cleanup costs of the spills he's encountered range from $100,000 to $250,000.

The holes that cause the leaks tend to be small.

"They are not much more than a couple of millimetres in diameter, but that's enough to drain a full home fuel tank in just over 24 hours," said Kent.

He recommends homeowners check their insurance policy to see what and how much coverage they have in the event of a spill.

"The fifty bucks you saved with cheaper insurance won't be a bargain when you have a $100,000-plus claim denied," he said.

At one of the most recent spill cleanups Kent supervised, the homeowner's insurance claim was denied. When the person renewed their insurance last year their policy changed to not include the cost of oil spill leaks.

The spills can be difficult and costly to clean up.

"I had to pull out two trailers from their lots," said Kent. "The leak got into the water and sewer trenches then took off in other directions."

In another instance he said the leak went through a basement and they had to break the concrete floor.

Under the NWT's Environment Protection Act the homeowner is legally responsible for the costs associated with cleaning up the spill.

Glen Abernethy, MLA for Great Slave, brought up the issue of leaky tanks at the legislative assembly last October.

"It can be very expensive," said Abernethy. "In the (legislative assembly) I asked the minister to a put out public awareness literature."

In the beginning of February the Department of Environment and Natural Resources released a publication on their website titled, "Homeowner's guide to oil tanks."