Four people were killed in a car crash early Tuesday morning on B.C.’s Highway 1, according to Mounties.

Authorities have identified the deceased as BC Wildfire Service sub-contractors who were travelling home after assisting with fire suppression efforts near Vanderhoof, in the Prince George Fire Centre.

“This year has been particularly challenging for the BC Wildfire Service, with several of its members facing injuries or losing their lives. Our thoughts are with the friends and family of those who help keep our province safe,” said Cpl. James Grandy in a news release issued Wednesday.

Police said the collision happened around 2 a.m. near Walhachin, which is about 70 kilometres west of Kamloops.

The crash was between a semi-tractor trailer and a Ford F-350 pickup truck. The semi caught on fire, but the driver was able to escape, according to police.

All four occupants of the pickup were pronounced dead at the scene.

“Initial investigation determined the pick-up truck failed to navigate a bend in the road to the right, crossing the centre line and colliding with the semi truck head on,” RCMP wrote.

Highway 1 was closed in both directions for the investigation but has since reopened.

In a joint statement Wednesday, Premier David Eby and Minister of Forests Bruce Ralston offered condolences to the family, friends and colleagues of the fallen firefighters.

This is devastating news in what has been an immensely difficult wildfire season. We stand with wildfire fighters and all BC Wildfire Service personnel as they mourn the death of colleagues and co-workers yet again,” they wrote.

Firefighters are on the front lines in so many parts of B.C., creating hope from despair and working tirelessly to save lives and livelihoods. Words cannot express the depth of our gratitude.

This wildfire season has been a deadly one for first responders. Now six firefighters have lost their lives in B.C.

On July 28, 25-year-old Zak Muise was killed while battling the Donnie Creek wildfire—the biggest on record in the province—when the UTV he was a passenger in went down an embankment.

On July 13, 19-year-old Devyn Gale died in the line of duty near Revelstoke. She was found under a fallen tree.

BC Wildfire Service told CTV News it is unable to name the four killed Tuesday as the collision remains under investigation.