CONCORD -- A one-alarm fire that sent smoke seen from a mile away destroyed four cars and a travel trailer at an industrial building property Wednesday night, a Contra Costa Fire Protection District spokesman said.

Nobody was on the property at 2250 Via de Mercados, off Concord Avenue, when the fire started around 11 p.m., and nobody was injured fighting the blaze, Fire Inspector George Laing said. The property houses a tow yard and a U-Haul rental facility.

Crews could see dense smoke from a mile away, and when they arrived, a couple of smaller buildings not connected to a larger main building were fully ablaze, Laing said. Inside one of those buildings, two vehicles and a an undisclosed amount of propane tanks also were burning.

Emergency vents inside the tanks designed to reduce pressure prevented them from exploding, Laing said.

Twenty firefighters extinguished the blaze in 35 minutes, and the main building was unscathed, he said. But four vehicles and a travel trailer were destroyed, as was 150 feet of corrugated siding, Laing said. In all, damages to the property and vehicles were estimated at $250,000, he said.

Contact Rick Hurd at 925-945-4789 and follow him at Twitter.com/3rdERH.