The Colorado Department of Transportation is reducing Boulder Canyon to one lane at a site west of Magnolia Road for several weeks while crews work to clean up the diesel-fuel spill that occurred there earlier this month.

The lane reduction, which CDOT officials said is now underway, is at the 34.6 mile marker of Boulder Canyon Drive, which is about 3 miles west of Magnolia Road, through at least January.

On Dec. 2, a truck carrying 4,000 gallons of diesel fuel was involved in a roll-over accident at that site, and much of the truck's fuel load spilled.

Ashley Mohr, a spokeswoman with CDOT, said the delay in cleanup is due to the search for a contractor to handle the job. With a contractor now on board, Mohr said crews will need the lane while they work to remove contaminated soil next to the road.

"A lot of it is off the road, but we just need one lane closed so we can get crews in," Mohr said.

The closure will remain in place throughout the cleanup, and traffic will alternate in the one open lane. When crews are working during the week, flaggers will direct traffic, while a signal with a three-minute timing cycle will be in place to direct traffic when crews are not on scene.

CDOT advised drivers should leave 10 minutes early for their destination and drive slowly through the area.

Mohr said the work will take at least until January, and might last longer depending on weather conditions and how much soil was contaminated by the fuel. She said tests will be done to determine how much soil needs to be removed.

"We're taking every precaution to make sure it's all removed," she said. "We're still assessing how much of it got into the soil. The ground wasn't frozen at the time, so it was all basically absorbed by the soil."

According to the Colorado State Patrol, speed and "driver inexperience" may have led to the crash on Dec. 2. The driver of the truck, Reed Kreutzer, of Thornton, was wearing a seatbelt and was not injured, but was cited for careless driving, according to the state patrol.

Contact Camera Staff Writer Mitchell Byars at 303-473-1329, byarsm@dailycamera.com or twitter.com/mitchellbyars.