A cement mixing lorry and a JCB vehicle were destroyed in a suspected arson attack near Higher Walton Mills near Preston.
Firefighters and police were called to the scene at around 4.45am on Sunday.
Two fire engines attended the incident, inside a secure compound.
Crews used hose reels, breaking in tools, a ventilation unit and lighting rigs to put out the fire.
Watch manager Mark Noblet said: “We’re treating it as a deliberate fire. It was outside in the yard and it affected two vehicles, a cement mixer and a heavy duty forklift truck.
“We contained it to the vehicles. There were wooden pallets either side so it was a good effort on our part to stop it spreading. When we got there we thought they were on fire.
“We were there for about an hour and a half.”
He said a JCB Loadall was 80 per cent severely damaged by fire and a HGV Ready Mix lorry was 100 per cent severely damaged by fire.