No one was injured in an explosive fire that destroyed a greenhouse on North Whidbey Monday morning.

At 8:15 a.m., North Whidbey Fire and Rescue and Central Whidbey Island Fire and Rescue were called to respond to a fire on Glencairn Road, just north of Penn Cove.

North Whidbey Fire and Rescue Chief Chris Swiger said the fire was caused by a propane heater that was kept on overnight. He advises against doing this as the heater is not monitored.

One of the four 100-pound tanks involved exploded as a result of what is called a “BLEVE,” which stands for “boiling liquid expanding vapor explosion,” Swiger said.

A BLEVE occurs when the pressurized liquid inside a vessel has a temperature higher than the boiling point at atmospheric pressure. If the container breaks, the loss of pressure causes the liquid to convert into gas, causing an explosion.

“It’s a huge explosion,” he said.

Swiger said the homeowner was on the phone with a dispatcher when he witnessed the blast, which was also heard by multiple Facebook users in the area.

Most of the approximately 10 by 20 foot greenhouse was burnt by the time firefighters arrived at the scene. The flames were so hot they cracked the window of the homeowner’s garage, which was about 25 feet away from the buning structure, Swiger said. The fire also melted “a bit” of the tractor. The house, which was about 20 feet away from the greenhouse, was left unharmed.

It took about 10 minutes to fully contain the fire, Swiger said, adding that it could have been much worse.