Residents and drivers on North River Road in Kings County are being warned to close their windows and stay inside to avoid breathing in what could be toxic smoke from a nearby construction debris fire.

Brian Desloges, the supervisor of public safety for the county, said the dump is "a mounded pile of debris," about 91 metres long, 45 metres wide, and approximately eight storeys tall.

Jeff Martin, deputy chief of the Kentville Fire Department, says the fire has been burning since Tuesday afternoon, and firefighters likely won't be able to put it out until Friday.

"Just the amount of work that's involved … we have to completely tear the pile apart with excavating machines and cover it, damp it down, and make sure that the fire's completely out before we're done here," Martin said.

Firefighters are using two 30-metre ladders to get above the fire, and try to smother it with sand and water, he said.

Unclear which materials are burning

Desloges said residents in the 3000 to 4000 block of North River Road should keep their windows and doors closed until the fire is out. Drivers on Highway 12 should also keep their windows closed, as a precaution.

Martin said it's difficult to tell exactly which materials are on fire.

"We're seeing wood products, shingles, we do have some plastics. I'm just looking at it right now — we have some mattresses that I can see, carpets — it's a pretty good mixture of stuff in there."

There is no confirmation that the smoke is toxic, Desloges said.

"We're not worried that this is actually a health hazard," he said. "But it is smoke and for some people who have asthma, who have breathing difficulties, for the elderly, this would just aggravate whatever condition they have."

Too early to identify a cause

Desloges said he doesn't see the need for RCMP to go door-to-door to warn residents about the smoke.

"It's a very remotely populated rural area," he said. "Mostly cottagers. The population per square mile here is really, really low … this probably would not affect more than 50 cottages and full-time residents."

Firefighters aren't sure of the cause of the fire, Martin said, because they can't get close enough to start their investigation.

He said roughly 50 firefighters are on scene from five volunteer fire departments. Due to long working hours, they plan to stop actively fighting the fire at night, Martin said, leaving somebody at the scene to monitor the blaze.