People working in the oil furnace repair industry say something is causing potentially costly problems for Nova Scotians who heat with furnace oil.

Shannon Gotell, who works for A.S.A.P. Burner Service, said he’s noticed a big increase in the number of leaking pump seals this winter over previous winters.

“For the first month or so I noticed, I was like, my God I'm going through an awful lot of pumps, more than normal. I just thought maybe it was a coincidence,” he said.

Once Gotell starting talking to other furnace repair people, he realized he was not alone. So far this winter, he said he's replaced about 30 oil furnace pumps — twice as many as usual. All of the pumps had leaky seals.

Because the seal is encased inside the pump, there's no way to check the seal to ensure it's in good shape.

John van der Meer was on vacation during the winter of 2012 when the pump seal on his furnace failed. No one noticed for a day and a half. His insurance company paid $200,000 to clean up the oil leak.

furnace pump seal

Because the seal is encased inside the pump, there's no way to check the seal to ensure it's in good shape. (CBC)

“What started as a small test hole in the basement floor to see if they could detect oil ended up with half the yard excavated and a huge project that lasted from mid-December until about March,” said van der Meer.

He said the cleanup cost as much as his home, so without insurance he's not sure what would have happened.

The increasing number of seal failures this winter has many in the industry speculating about  the cause.

For years, furnace oil came from the Imperial Oil Refinery in Dartmouth. When it closed in September, oil for the Nova Scotia market had to be sourced from elsewhere. That has lead some to believe additives of some sort are to blame.

“I don't know what it is but whatever it is it's eating away the seals pretty rapidly,” said Gotell.

He said it’s not any one brand of pump with the seal problems, he sees it across several brands.

The best advice is to keep an eye on your furnace. If you smell or see oil, get it checked.

Environment Canada is responsible for regulating furnace oil. CBC News attempted to contact the department but has not received a response.