Authorities say 39-year-old Joseph Hills of Bucksport was on the Bayside Road, when he passed a car in a no passing zone at around four pm.
The other car was driven by 20-year-old Tanya Gilley of Dedham.
Hills hit an oncoming car driven by 54-year-old Cheryle Dyer of Trenton, then crashed into Gilley’s car.
Deputies say Hills also hit a car driven by 22-year-old Emily O’Connell of Hampden.
Hills, Gilley, and Dyer were all taken to Eastern Maine Medical Center.
O’Connell was treated at the scene, and released.