Methane, a combustible gas, has been discovered underground, outside the boundaries of a Kent County landfill.
The now-closed landfill is near Kentwood's City Hall.
Dar Baas, Kent County Director of Public Works, says methane usually vents up, into the air, but in this situation, some of it is moving horizonally, under the surface.
He says there will be increased monitoring in the area.
"We did some testing at the city office," says Baas, "and everything's coming back there non-detect, which is really good news. But we want to make sure we're thorough."