One person was killed in a two-vehicle collision west of Carleton Place, Ont., Friday afternoon, and a worker with the province was seriously injured while helping with the investigation, police say.

Ontario Provincial Police say a man was killed in the early afternoon crash on Highway 7 between a transport truck and pickup truck.

The crash happened between Tatlock Road and Ramsay Concession 4A, Lanark OPP said. The victim's name and age have not been released.

The OPP closed the highway between Tatlock Road and Townline Road as they investigated the cause of the crash.

2nd collision involving MTO worker

During that investigation, a driver collided with a vehicle from Ontario's Ministry of Transportation (MTO), police said in an update Friday evening.

An MTO worker who was assisting with the investigation suffered serious injuries, the OPP said. He was taken to a nearby hospital.

The second collision happened at around 7:30 p.m., along the stretch of Highway 7 that had been blocked off because of the previous crash, said OPP Const. Greg Streng.

As of 8:45 p.m., Lanark OPP had not yet opened the highway.

Police are detouring drivers around the scene of the crash and are asking travellers to plan a different route.

Highway 7 is expected to be closed for several more hours as the dual investigations continue, police said.