Elisa Shackelton: Clean magnesium chloride off your car frequently


— A pair of recent research projects detailed some of the environmental impacts of using magnesium chloride as a highway de-icer in the winter and as a summer dust-suppressant on unpaved county roads.

The research shows both uses of the chemical cause extensive damage to roadside vegetation. That may be a no-brainer for people in mountain communities who have seen red and dying trees along local roads long before the current pine beetle epidemic jumped into overdrive.

In another study, Colorado State University researchers directly recommend against using magnesium chloride for dust suppression in forested areas. The study showed that roadside plants absorb the chemical as it runs off roads. The chloride directly harms vegetation and also hinders water uptake. Trees in the study areas suffered extensive damage from exposure to mag chloride. The research also showed the mag chloride gets spread far from the road - up to 300 feet - as it's sprayed by passing trucks and cars.

What's mag chloride doing to your car?

In the winter of 2006-07, the Colorado Department of Transportation used about 9 million gallons of magnesium chloride to keep roads ice-free. CDOT spreads magnesium chloride - a salt compound - on state roads such as Interstate 70 to melt ice and snow. Use of the de-icer, which comes from factories along Utah's Great Salt Lake, now has been expanded to secondary highways in Colorado; application has increased 1,400 percent in the past eight years, to 10.62 million gallons.

Some mechanics and others say they are seeing the substance corrode vehicle components, making them unsafe. And the adhesive mixed with mag chloride makes it difficult to remove from vehicles, requiring the substance to be removed with either with hot, soapy water or a pressure washer. If not removed, mag chloride begins to corrode components essential to safe operation of vehicles, such as brakes. The most common brake corrosion occurs on passenger-side brakes, where the tires hit pools of mag chloride along the right side of roads. Auto mechanics interviewed in Colorado mountain communities believe that mag chloride is corroding rubber car parts faster than in the past, too. They also are seeing windshield wipers lasting half as long as they used to, as well as all kinds of corrosion underneath the car. Electrical components, covered in plastic, often corrode and trip 'check engine' lights. Because of the potential for corrosive damage to vehicles, people should clean their cars frequently, especially the undercarriage, during the winter months.

For more information, contact Elisa at the CSU Moffat County Extension Office, 539 Barclay, 824-9180.


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