Interstate 395 North is closed in Thompson and officials from Quinebaug Valley Emergency Communications said the highway will be closed for most of the day.
The CT Travel Smart website says the highway is closed between exits 50 and 53 because of a paving equipment fire.
Quinebaug Valley Emergency Communications supervisor Travis Irons said a machine with more than 20 tons of asphalt burned and there is a significant diesel leak from equipment.
Crews from the state Department of Energy and Environmental Protection responded to the scene.
No additional information was immediately available.