Jun. 12—TRAVERSE CITY — The source of a mysterious spill on a U.S. 131 roundabout in Fife Lake a week ago was confirmed as a truck brining roads in Grand Traverse County.

The slippery substance, later identified as a non-hazardous calcium choride solution used in brining, closed the highway on the evening of June 5 for hours so the Fife Lake Springfield Fire Department could clean up the spill.

A tanker truck operated by Great Lakes Chloride, and retained by the county road commission to brine roads, was the source of the spill, said Zach Clothier, a GLC representative in Michigan.

“The truck had a leaking valve and the operator stopped to close it tightly after noticing the leak,” Clothier said.

The roadway reopened at 1:15 a.m. June 6.

Dust control on gravel roads in the county is a high priority right now for a number of reasons: Not only does dust reduce visibility, it can wear down mechanical systems in vehicles. In addition, according to a 2022 scientific study published in the journal Environmental Science Technology, road dust and other non-exhaust fine particles may be associated with acute and chronic cardiovascular issues.

This year, the road commission will spend more than a quarter of a million dollars to control road dust through this process called “brining.”

The costs to do this are typically shared with townships on a 50-50 basis. And the county road commission contracts with GLC to do the work.

“Our contractor completed brining 176 miles of gravel roads in the county last week,” said Larry LaCross, superintendent of field operations for the road commission.

“We try to get the dust control done before Memorial Day,” LaCross said, “but, this year, there was a shortage of the (brine) material and we had to apply our first application the week of June 3.”

Another 160 miles of gravel roads were not brined in the latest round, primarily because they’re too small for the large brine tanker trucks to turn around on.

This year, the county is paying just under 86 cents per gallon for brining solution. Brining one mile of gravel road takes about 1,900 gallons of brine, which equals about $1,630 per mile. (In contrast, one mile of new paved road costs about $2 million to build.)

All of the county’s townships participated in this month’s brining process. A second round of dust-control brining will occur later this summer or fall. But not all townships request the second round, Lacross said.

WHAT IS BRINING?

Brining involves spraying a liquid solution of calcium chloride and water on gravel roads using tanker trunks with special sprayers mounted on the lower back. The solution adheres to dust, clay particles and other fine material on the roadway.

Because calcium chloride is a “hygroscopic salt,” it tends to attract ambient moisture from the environment, extending its dust-control effectiveness and reducing sediment run-off into nearby streams and rivers.

Calcium chloride also resists evaporation, which enables one application to last a long time. The occasional rain can help reactivate the solution, according to industry officials.

Before brining is sprayed, all the gravel roads targeted for work need to be graded or bladed, officials said. Blading involves shaping the crown or slope of a roadway, as well as related berms and drainage dips, to prevent water from accumulating on the surface.

Not only does brining help improve safety for road users and decrease exposure to dust particles, it can also reduce maintenance costs related to gravel road blading and replacement.

GLC, headquartered in Warsaw, Indiana, uses a calcium chloride solution called “Liquidow,” which consists of 53—72 percent water (by weight) and 28-42 percent calcium chloride. It also contains less than 3 percent of potassium chloride and calcium chloride (table salt).

Calcium chloride brine is not considered hazardous or carcinogenic, according to federal regulators, although it can irritate the skin and eyes through direct exposure. Walking in shoes along a recently brined road is not considered direct exposure.

“If you’re walking barefoot along a road that’s still wet from brining, just wash it off with water,” Clothier said. “We don’t use oil-based brines at all.”

Calcium chloride solution is one of four products approved by the state Department of Environment, Great Lakes and Energy (EGLE) or road brining without a permit, he said.

“When we apply the dust control, the surface is wet for some time,” Lacross said. “I would wait until the Liquidow soaks into the gravel and becomes dry before letting your pets walk on the area of application.”

ENVIRONMENTAL DEBATE

The use of salt-based products, such as road salt and brine, is the topic of debate between state regulators, environmental groups and county road commissions.

Michigan has some 36,000 miles of unpaved roads, many of which are treated with brine to tamp down the dust.

In recent years, runoff from chlorine-based materials has severely affected water quality in areas like Church Lake in Grand Rapids, according to researchers at Grand Valley State University.

The region’s reliance on rock salt is even salinating Lake Michigan, according to a 2023 report by Bridge Michigan. Toxic algae blooms caused by nutrient overgrowth is also a growing problem across the Great Lakes region.

However, chlorine levels in lakes and waterways may be more related to the sodium chloride used in rock salt, rather than the calcium chloride used for dust-control brining.

Tests show that calcium chloride is less harmful to plants and less corrosive to metals than sodium chloride, according to the U.S. Environmental Protection Agency.

Today, sodium chloride (“rock salt”) is the most common substance used for deicing roads and highways, largely because it is much cheaper, EPA officials noted. In comparison, calcium chloride can be up to three times more expensive, they added.

Because of looming price increases for calcium chloride, the county road commission took action earlier this year to lock in brining contracts at a lower cost, earning praise from county commissioners.

Attempts at regulating chlorine-based road products in Michigan have met with little success.

Last year, state EGLE officials proposed new limits on road brining, but retreated after heated push-back from county road commissions who said there was no effective alternative to calcium chloride brine.

Other possible brine solutions, such as oil-based brine, agricultural byproducts and asphalt emulsion, are just as bad — or even worse — from an environmental standpoint, according to Bridge Michigan.

Ultimately, the future of road brining in Michigan may depend on more in-depth environmental and chemical studies, data from which could then support more informed decision-making at the regulatory level.