HOQUIAM, Wash. – An explosion at the Imperium Biodiesel refinery Wednesday afternoon forced the evacuation of several nearby businesses.
Experts are now assessing the damage and trying to figure out what caused the chain reaction.
Authorities say all plant workers have been accounted for and are safe.
The Imperium Biodiesel refinery is one of the largest of its kind in the world and, while it's not producing right now, it is storing thousands of gallons of potentially dangerous materials.
The tank reportedly contained glycerin, which is a harmless soap ingredient on its own but can be mixed to nitroglycerin or in the case of biodiesel production mixed with sulfuric acid. A large chunk of the tank was blown at least 100 feet away and crashed through a chain link fence.
The nearby tank of sulfuric acid was ruptured and spilled an unknown amount of acid, which can be dangerous if it comes in contact or is breathed as a mist by people.
One worker at a business a few blocks away heard the explosion and felt the percussion.
"We heard a loud bang and it sounded like it came from the roof, and everybody looked at each other with puzzled looks and then one of the guys from the back shop came running in and and he thought Imperium just blew up because there's a big cloud of smoke over there," he said.
A similar explosion happened at a Chicago Biodiesel Plant back in July. Several people were injured in that blast. The cause of that one was an improper mixture of glycerin and sulfuric acid.