PORTLAND, Ore. (KOIN) — A large fire that spread to several outbuildings and vehicles caused propane explosions in Sherwood early Thursday morning, according to fire officials.

Tualatin Valley Fire & Rescue tweeted that crews were working a blaze at around 2:45 a.m. on Dahlke Lane. There were vehicles shipping containers and sheds scattered across the property that caught fire.

Fire officials said five people were inside recreational vehicles but made it out safely.

As the blaze ravaged on, TVF&R said several propane tanks exploded. Crews eventually knocked the flames down and got what they called a “challenging” fire under control.

An official with TVF&R told KOIN 6 crews worked cautiously because of the risk of propane explosions. They also said crews had to shuttle in water on their own since there is no fire hydrant nearby.

An investigation is underway to determine what caused the fire.