A five-year ban on the use of magnesium chloride on roads in Larimer County may be lifted in some instances should local residents agree.
Magnesium chloride in its liquid form is frequently used by county highway departments as a de-icer, to control dust and erosion on dirt and gravel roads, and at job sites.
The Colorado Department of Transportation has used mag chloride — or related substances — for at least 20 years on icy roads because it’s more effective than just rock salt and sand, CDOT spokeswoman Stacey Stegman said.
But Larimer County stopped using the substance five years ago, after a Colorado State University study concluded the substance is toxic to trees and other roadside vegetation.
However, the county may be ready to reverse itself, at least when it comes to unpaved roads in public improvement districts, said county road and bridge director Dale Miller.
Three public improvement districts near Estes Park and Pinewood Reservoir have asked for permission to use mag chloride on privately maintained roads for stabilization and dust control.
“They said there are other products out there that are more expensive and less effective than mag chloride and they want to go back to mag chloride,” Miller said.
The county commissioners agreed this week to let the districts decide and then consult with Miller, who will make the final ruling.
“They know their road situation better than I,” County Commissioner Steve Johnson said Tuesday. “They care about their trees and understand the situation more than I do. If they see a need, I think they should have the flexibility to do that.”
Miller said he will weigh each request, giving heavy consideration to any potential environmental damage.
“I think in any situation, we have to pay attention to our surroundings, and we have to be judicious in the use of any materials we use,” he said.
After testing other products — including organic de-icers and stabilizers — CDOT concluded that based on cost and environmental impact, mag chloride remains the best product to use on roads, Stegman said.
“There has certainly been controversy surrounding mag chloride in the past, and there has also been a lot of misinformation surrounding its use,” she said. “Anything you use has a downside.”
Last winter, CDOT bought mag chloride at 62 cents per gallon and used 500,000 gallons on state roads.
“Overall,” she said, “mag chloride is the least damaging to the environment and the most cost-effective.”
Larimer County currently uses chloride products along with sand and salt on its paved roads, but it may consider lifting the entire ban and use mag chloride exclusively, Miller said.
“I think sometime this spring or summer,” said Miller, “we will probably go to the commissioners and have a discussion about using mag chloride on all county-maintained roads.”
Monte Whaley: 720-929-0907 or mwhaley@denverpost.com
