Waltham, MA - On the morning of October 30th, Waltham Engine 4 and Medic 1 responded to 5 Guys at 1030 Main Street for an employee who had fainted. She was transported to Newton Wellesley Hospital. At 12:30 P.M., Engine 4 and Medic 1 responded back to 5 Guys for a similar incident. They cleared the restaurant. C2, Deputy Capello arrived and requested Tower 1 and Rescue 1 to respond. Over all, four employees were transported to Newton Wellesley Hospital. High carbon monoxide was detected and a tier 1 hazmat incident was declared to help find the source.