Central Hastings OPP said two paramedics were taken to a local hospital after an ambulance collided with a transport truck.
One was later airlifted to a regional trauma centre with life-threatening injuries.
Officers responded just after 3 p.m. Monday to the collision in Madoc at the intersection of Highway 7 and Highway 62.
Two occupants of the transport truck were also taken to hospital as a precaution.
Police said the intersection was closed this morning while repairs to the traffic lights were completed, but it has reopened.
Police continue to investigate and are asking anyone with information or dash cam footage to contact them at 1‑888‑310‑1122 or Crimestoppers at 1‑800‑222‑TIPS (8477).
