Tanks at Imperium's Grays Harbor facility. Company photo.

KOMO News is reporting that a "thunderous explosion" rocked the Hoquiam area earlier this afternoon after a 3,000 gallon glycerin tank at the massive Imperium Renewables biodiesel plant exploded. KOMO reports that a tank became overpressurized and exploded at about 2:30 p.m. No injuries were reported, though some nearby businesses were evacuated by firefighters.

The explosion marks yet another setback for Imperium, a one-time high-flyer which fell on tough times over the past two years as the biodiesel market failed to take hold. Imperium has lost key contracts over the past 24 months and laid off staffers. [Post updated with statement from Imperium]

In June, Imperium sold off its Seattle biodiesel facility, focusing efforts on the 100 million gallon facility in Grays Harbor County.

According to Imperium's Web site, the company sells crude glycerin which is a co-product of the refining process.

We're awaiting a statement on the situation from an Imperium spokesman, and will update this post when we hear back.

UPDATE: Here's the statement issued by Imperium:

At approximately 2:30 pm Pacific Time today, a glycerin processing tank in the glycerin refining section of the Imperium Grays Harbor biodiesel plant ruptured as a result of over-pressurization. There were no injuries and no fire.

The 10,000 gallon tank contained heated glycerin. As a result of the rupture, heated glycerin in the tank mixed with the cold air creating a large vapor plume. The glycerin, a co-product of biodiesel production which is a dark, liquid non-toxic substance that resembles molasses, was spread across the incident area, giving the appearance of charred material.

In addition, the rupture damaged nearby pipes and two adjacent tanks, containing biodiesel and other materials used in the refining of glycerin, including sulfuric acid held in a 5000 gallon tank provided by the vendor. The processing tank and other tanks are located in a fully contained area, and as such the liquids and other materials do not pose a threat to the area. No other tanks were impacted.

The insulation on the glycerin processing tank was wrapped in an aluminum cover. The force of the rupture scattered aluminum and insulation across the Imperium Grays Harbor property and adjacent property.

The company has instituted its emergency response plan and is cooperating with the police and fire departments and other appropriate authorities. When company officials are given access to the incident area, they will conduct a thorough investigation to determine what happened, and commence clean-up operations.

The company has shut down operation of the plant, which will remain idle until the extent of the damage is known. The company is extremely thankful that no one was injured.

As more information and facts become available the company will send updates to the media and post information on the website.

John Cook is co-founder of TechFlash. Follow on Twitter @johnhcook.