COLORADO SPRINGS, COLO. -- Crews have opened northbound I-25 at Bijou Street in Colorado Springs after the interstate was closed for around seven hours Thursday morning while crews worked to clean up a milk and fuel spill after a milk truck rolled over.

"Milk is a hazardous material. We also have diesel fuel mixed into that, so the combination of both of them is not good for our creeks or streams or anything getting into the ground," Sunny Smaldino with the Colorado Springs Fire Department said.

Colorado Springs fire crews responded to the scene around 4:20 a.m., closing all northbound lanes and diverting traffic onto Nevada Avenue as they worked to clean the spill and get the milk tanker truck upright.

The driver was trapped in the truck when it rolled and was taken to the hospital with life-threatening injuries, but authorities have not released an update on his condition.

"The fortunate thing was they were able to get him out very quickly, and within 25 minutes he was extricated and at the hospital in the ER," Smaldino said.

The driver is an employee of Western Dairy Transport, which is based in Missouri.

An employee said he has been a driver there for several years.

Officials said traffic was backed up all the way into Fountain as drivers were significantly delayed in their morning commute.

"I know it's a tough thing to get to work on time in general, and to have this be one of those things, it's just great that we can have some understanding community members," Smaldino said.

Police said the cause of the crash is still under investigation.

Click here for photos from earlier Thursday morning.