Wilton fire officials say a private company tried to clean up an oil spill this morning, but unintentionally started a small fire and sent potentially hazardous chemicals into the air. Firefighters say they were called in at around 9:40 a.m. to battle a blaze on Pond Road. They say the company mixed two substances in an effort to clean the earlier spill. The substances caught fire and emitted the gases. Local roads were blocked off as emergency crews responded to the scene. Residents were required to remain inside their homes until the situation was resolved. Fire officials say the incident did not affect drinking water.