rock salt, halite, mineral form of table salt
Timothy Jacobsen/AP

High Rock Salt Prices Leave Municipalities Looking for Alternatives

November 28, 2008 01:59 PM
by Anne Szustek
Steep increases in rock salt prices are forcing city ground crews to explore other ways to keep local roadways ice-free this winter.

Deicing Methods Come at a Salty Price this Winter

Snow and ice have already descended upon much of the Midwest, marking the start of the season of cautious driving, snow emergency route parking and salty roads.

Rock salt is often the go-to cure to keep roadways relatively free of snow and ice. But this year, with rock salt prices up as much as 300 percent from last year in some areas, governments are looking at their winter roadwork budgets with raised eyebrows—and searching for budget-saving strategies.

The Illinois state attorney general’s office is investigating possible rock salt price gouging across the state. In Moline, part of the Quad Cities area along the Illinois-Iowa border, rock salt prices shot up three fold from last year. Greater Rock Island County, where Moline is located, as well as some Chicago suburbs, have also asked the attorney general explore the reasons behind the rock salt price hikes. ‘‘The public deserves a plausible explanation’’ why some side streets will not get as much salt this winter, Doug House, Moline’s manager for municipal services, told Illinois paper The Southern.

The Ohio Department of Transportation, which has estimated that the price of rock salt has gone up $15-20 a ton from last year, has a three-pronged strategy to cut back on salting: pre-treating roadways with a brine solution, mixing calcium chloride in with traditional rock salt in extremely cold temperatures and using trucks equipped with special sensors to gauge exactly how much salt needs to be doled out.
“We can save a lot of salt by using brine,” Larry Earman, a trustee chairman of Norwich Township, Ohio told Columbus Local News. With snow reported in the region, central Ohio has already had a chance to test out brining.

Distributors of a chemically treated rock salt called “Magic Salt,” are pushing for its use on Cleveland roadways. While Magic Salt has a higher initial outlay, according to Fox Cleveland sources, its melting power lasts longer and leaves less of an environmental imprint.

“It’s widely used in New York. They’ve been using it over 10 to 12 years on their bridges,” distributor Dwayne Mauer, told Fox Cleveland. “Because it’s non corrosive, it doesn’t eat their steel.”

North Dakota has dabbled in another rock salt alternative: reusing wastewater from oil fields. The N.D. Health Department has given the practice the go-ahead; however oil companies are reluctant to give away the water and municipalities are not wont to use it, out of liability concerns. 

North Dakota used oil field wastewater to deice roadways between 1963 and 2007, when the AP reported on the procedure. The Transportation Department does not plan to use oil field wastewater this year; however, state Transportation Director Francis Ziegler told the AP, “Never say never—if the cost of road salt keeps going up, we may look at it again.”

Key Player: Rock salt

Halite, table salt in its mineral form, also known as sodium chloride, is the most commonly used deicer. Saltwater has a lower freezing point than water, so when salt is thrown upon snow and ice, it more easily evaporates or is removed.

Calcium chloride
is used as a deicer in extremely cold weather. When it touches water, an exothermal, or heat-releasing, chemical reaction occurs, helping melt accumulated precipitation.

One caveat of using calcium chloride is that its characteristic exothermal reaction can “burn” living things, as was the case on some mountain roads in Washington state last winter. Jim Hatfield, a forest pathologist working for the Wenatchee-Okanogan National Forest, told the AP in March that although his office had not embarked on a formal study of the phenomenon, some trees have died as a result of contact with the calcium chloride deicer.
“I would definitely say it’s something we should be looking into more in depth,” Hatfield told the AP. But Doug Pierce, the Washington Transportation Department environmental operations manager, maintains that the damage is slight and trees can easily recover during the warm-weather months.

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