De-icing dilemma has expensive alternatives
But one mountain town, Avon, hasn’t waited for the verdict to dismiss the de-icer, commonly known as “mag chloride.”
That decision has been expensive, says Avon’s Public Works director, Bob Reed. The chemical Reed and his crews used predominantly – Calcium Magnesium Acetate, or CMA – costs about 23 times more per ton than mag chloride, which Avon also uses, but sparingly, Reed says.
“We have always used the CMA. It doesn’t kill plants, it has a low toxicity to fish – it’s just generally one of the best products on the market,” Reed says.
But CMA costs $1,400 per ton compared to just $60 per ton for mag chloride – 600,00 gallons of which is used by state highway crews on Interstate 70 from Wolcott to Vail Pass and on U.S. Highway 24 to Leadville.
“(Magnesium chloride) is one of the tools we use and it’s proven effective,” says Keith Powers, the Colorado Department of Transportation’s engineer in Eagle County. “Other than that, we’re always trying to find better products.”
Despite widespread complaints mag chloride corrodes cars and trucks, science, so far, hasn’t found any more damning evidence against the de-icer than forcing folks to wash their vehicles more often.
For one, mag chloride has been credited with reducing car crashes – by as much as 300 percent on some stretches of I-70, according to the department of transportation.-
“I think the case that this stuff is outright dangerous is very hard to make,” said University of Colorado Professor William Lewis, who studied the toxicity of mag chloride on I-70 in Summit and Clear Creek counties for three years.
Lewis has also studied the impact of magnesium chloride on aquatic organisms.
“We don’t have any field evidence of negative effects of mag chloride on aquatic organisms,” he has said, adding the substance is typically diluted to levels where it does little damage once it leaks into streams.
Lewis, however, has noted chloride “burns” on roadside trees. The phenomenon is well known on the East Coast where sodium chloride is mixed with road traction sand, he has said.
“It doesn’t kill the tree, it just turns exposed branches brown,” he said. “It’s unsightly but it doesn’t extend very far from the road.”
The Colorado Association of Ski Towns, an industry advocacy group, has also studied magnesium chloride.
“It appears that these de-icers pose no worse human health impacts than do street sand/salt mixtures,” that study concluded.
Eagle County also uses the chemical in small amounts during the summer to control dust on gravel roads.
But some say less chemicals could be used to de-ice highways if drivers slowed down. The department of transportation is just responding to the public’s demands for ice-free roads, John McCarty, a landscape architect who worked on the Glenwood Canyon re-vegetation project, has said.
“We need people to say, “I agree to go at a responsible speed on snowy days,'” McCarty has said. “It’s us as a whole. It’s easy to point a finger, but not many people point a finger at themselves.”
The High Country de-icing dilemma, however, goes beyond just mag chloride.
Traction sand, dumped on roads in heavier amounts before magnesium chloride came to Colorado, has been blamed doing far more serious environmental damage to streams alongside I-70.
Millions of dollars are now being spent to keep any more sand from pouring into Black Gore Creek above Vail and Straight Creek above Dillon. Scientists say the sand is choking off the streams and threatening fish, insects and plants.
Reed says Avon’s decision not to use mag chloride has much to with the inevitability of everything dumped on Vail Valley roads oozing into its rivers.
“I think living on the Eagle River, we need to be conscientious about what we’re eventually dumping in there,” he says. “We want to do our part not to harm environment anymore. We experimented with mag chloride and we didn’t like it – for one, it was hard on the equipment.
“Some other products work great on snowmelt,” he adds, “but dumped in river, it’s toxic to fish. Eventually, everything makes it back to the river.”
Unfortunately, spending cuts in Avon have forced Reed and his crews to use more mag chloride and other chemicals known as “ice slicers.” This year, the crews have used more volcanic cinders to give cars better traction and reserved the costly CMA for bridges and shadier spots.
“We’re always experimenting. We’re always testing new products that come out,” Reed says. “If you dumped CMA directly into the river, it might deplete oxygen while it’s dissolving, but after that it’s pretty harmless.
“The acetate,” he adds, “is about as harmful of a tablespoon of regular household vinegar. That’s what it kind of smells like, too.”
Vail Daily reporters Cliff Thompson and Randy Wyrick contributed to this report.