Fire heavily damaged a condominium unit at the Clayton Commons development just after midnight Saturday, and sent a number of residents into the night. The first fire units at the scene said they saw light smoke coming from the building. Executive aide to Springfield Fire Commissioner Bernard Calvi, Dennis Leger said the fire apparently started in the kitchen of the unit at 30 Clayton St., but the exact cause remains under investigation. Leger estimated damage to the structure at about $50,000. Three adults and one child escaped the burning unit with no injuries and are being assisted by the American Red Cross with their immediate needs. Leger said three pet turtles in the unit were found deceased.