A 40-year-old northeast Iowa man died after an explosion and fire last night in his auto repair shop in New Hartford, just west of Waterloo. Todd Johnson ran Todd’s Repair Shop. The cause of the blast is under investigation but foul play is not suspected. It may have been an overflow of oil. Investigators are back on the scene today. Johnson died at University Hospitals in Iowa City overnight. As a precaution, several apartments and four houses were evacuated as crews battled the fire.