As of Friday, officials still don't know what triggered a Wednesday afternoon blaze that consumed numerous giant bales of flattened cardboard, due to be recycled.

At least 30 firefighters from Umatilla County, Echo, Umatilla, Boardman and others responded to the fire on South Highway 395. Medelez Trucking owns the facility, and the fire was first seen around 1:30pm.

According to the East Oregonian, fire officials said cardboard fires are particularly difficult. If you've ever burned a box, you know how the flames and cinders just keep eating away, even when hit with water. Fire crews were even filling large containers, dozens of gallons, to help douse the flames.

Crews stayed on the scene for at least 5 hours or more, some officials said the boxes continued to burn through the night before finally being put out.  Officials had to briefly close Highway 395 due to the poor visibility from all the smoke.

Estimated losses were at least $60,000 worth of recyclable cardboard, and $5,000 in damages to equipment.