ELKHART, Ind. (AP): Officials say the flames are out at a northern Indiana landfill after a fire belching a huge plume of smoke burned for two days.

Crews continued work Friday putting soil over still smoldering sections of the landfill owned by Waste Management just south of Elkhart. The fire burned about 1 acre of the landfill, and planes and helicopters were used to dump water onto hot spots.

The Concord Community Schools called off classes Friday after closing early Thursday because of the heavy smoke, although health officials said initial air tests found no hazardous substances.

Waste Management spokesman Tom Horton says 35 mph winds prevented extinguishing the fire soon after it started early Wednesday.

Concord Township Fire Chief Rick Rochford says a cause for the blaze still isn’t known.