Barbara Lawlor, Boulder County. Boulder Canyon was closed for several hours on Tuesday, May 1, because of a hazardous material spill near Rogers Park. State Patrol estimated 250 gallons of sodium hydroxide leaked onto the pavement.

NaOH, at room temperature is a white crystalline odorless solid that absorbs moisture from the air. If dissolved in water it generates sufficient heat to ignite combustible materials. It is extremity corrosive to the eyes and skin and the respiratory tract. It is used in the creation of soap, detergent and drinking water, used to control ph levels. One CDOT worker was treated after a small amount of the liquid splashed his skin.

Nederland Fire Protection District, Sugarloaf Fire Protection District, Longmont Hazardous Material and City of Boulder Hazardous Material, the Colorado State Patrol, Boulder County Emergency Services, the Boulder County Public Health Department, as well as the Colorado Department of Transportation responded to the call around 9:30 a.m.

Sodium hydroxide, liquid lye, is used in Nederland’s Water Treatment plant, and was being transported by a private contractor. The canyon was still closed at 5:30 p.m. while clean-up crews worked along the creek shore. An undetermined amount of the caustic material drained into the creek and crews had to pressure wash the road, vacuum the liquid and scrape up all the dirt between the highway and creek.

Nobody was evacuated and City of Boulder Water Treatment plant was notified and they shut off their intakes.