It melts ice in winter. It degrades infrastructure year-round. Is road salt worth it?

man sprinkles salt on sidewalk

The Michigan legislature is again worrying about infrastructure. The state spends almost $4 billion annually on transportation, mostly on roads. Road salt is the destroyer of roads and bridges. Any plan to fix infrastructure should include getting away from road salt.

Let’s be clear about what constitutes “road salt.” Sodium chloride (common table salt) is the most common type, and may be applied to roads as rock salt or brine. Calcium chloride and magnesium chloride are sometimes called alternatives to road salt, but chemically, they are also salts.

The sodium ion is particularly hard on woody plants. But the chloride ion, which is common to all the above salts, contributes to the corrosion of concrete and steel, no matter which salt it comes from. While sodium chloride penetrates concrete more easily, calcium and magnesium chloride corrode vehicle parts more rapidly.

Michigan uses about 2 million tons of road salt annually. Two million tons is 4 billion pounds, or about 400 pounds of salt for each of the 10 million people who live in the state.

In purely financial terms, “USEPA estimates that every $50 ton of road salt causes approximately $750 in damage to concrete, bridges and vehicles.” Two million tons gets Michigan $1.5 billion in damages annually.

This means roads which otherwise would last for 20 years need to be fixed in 10. At the Zilwaukee bridge on I-75, road salt is now forbidden so it does not further weaken the spans. Road salt is also responsible for the rapid deterioration of I-75’s Rouge River bridge. Highway bridges that should last for over 50 years are visibly deteriorating in 20, and are unsafe 30 years after they are built.

Of course, it’s not just public infrastructure that is attacked by road salt. It also destroys cars and trucks. It corrodes wheels, brakes, electrical wiring, sheet metal and more. When spring comes, salt washes off roads and vehicles, increasing salinity in soils, groundwater and surface water. Farm fields near roads are now typically fringed with soil that supports only “salt tolerant” plants, not crops or native plants. Lakes that have taken years of salty runoff fail to “turn over” in the spring or fall, and the lake bottoms, deprived of oxygen, become dead zones.

Road salt played a part in the poisoning of Flint. The city water system started using water from the Flint River, which was 19 times more corrosive than water from the Detroit Water Department. What made the Flint River water corrosive? Chlorides.

The Genesee County Road Commission uses around 15 thousand tons of salt per year. If they tried to get an EPA permit to dump 15 thousand tons of salt directly into Lake Huron every year, we would think they were insane – and of course, the EPA would be insane to give them such a permit. In fact, after the Flint River, Lake Huron is exactly where most of the annual 15 thousand tons of salt ends up.

Macomb County is having issues with a sinkhole caused by sewer line leaks. In the winter of 2014-15, they used about 65,000 tons of salt. All that salt was washed into sewer lines. Could that cause unexpected corrosion?

Road salt is a prime example of short-term thinking over long-term. Several tons of salt on the road clears ice and snow for a day or two. If it snows again in a week, more tons of salt are spread. Again, the benefit lasts a day or so. However, once you get salt into the local water, you can’t get it out. Short term benefits are traded for long term damage.

A variety of organic de-icers in liquid form are effective, and are much safer for roads and bridges than salt. Most are made from agricultural by-products such as corn stalks or brewery waste. They are more expensive than salt. Safe de-icers could be used for critical intersections and bridges, leaving plowing and sand for the rest.

Any elected official who is not willing to discontinue road salt is willing to waste over a billion dollars every year. Ignorance is no excuse.

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Julie Watkins
Thu, 01/26/2017 - 4:24pm

Such a great point to remind everyone that all this stuff being "applied" must go somewhere and doesn't just disappear after the snow melts. I think of this daily in the winter driving in Michigan and it sickens me how much salt is getting into everything. I, for one, would be happy to see an organic substitute and better roads to boot!

Edward McArdle
Fri, 01/20/2017 - 9:08pm

wow! powerfully said.

Fri, 01/20/2017 - 10:08pm

In the mid -70's, I lived outside of Boston. Massachusetts gets it water from "reservoirs" - various lakes around the state, none as large as our Great Lakes and mostly unavailable for motorized recreation. In order to keep the water pure, only sand was used on roadways, never salt. That, coupled with plowing, kept roads fairly clear the 3 years I lived there.

veda balla
Sat, 01/21/2017 - 9:30am

Sharing. The condition of and need to improve our infrastructure is something we hear everyday coming out of the mouths of our elected or campaigning politicians. Also, environmental damage that can occur from using this salt is frightening. Getting officials to listen is another thing. A state like Michigan is particularly vulnerable to the effects of the salt, due to the huge amounts that are used here annually. An eye opening article.

Kevin Grand
Sat, 01/21/2017 - 12:05pm

Interesting premise.Yes, substitutes are more expensive, but what it the availability of those substitutes?Mr. Myatt, one thing that is missing from your piece is the fact that our society is <b>extremely dependent</b> on transportation than most people realize.It just goes without saying:<i>"If you bought it, a truck brought it!"</i>But if that truck cannot arrive because an adequate amount of material to de-ice the roads at your corner grocery store, pharmacy, local business, manufacturing plant, etc, and on schedule, the cost from that delay is only going to get magnified the more widespread those delays become.And I haven't even brought up the human costs should those examples above not get restocked in a timely fashion.

Art Myatt
Sun, 01/22/2017 - 10:17pm

The basic facts are easy to understand. We typically spend over $100 million annually on road salt (just the raw material, not the labor or equipment to apply it). It does well over $1 billion damage when applied. If, instead of buying road salt, we spent $800 million or even $1 billion on non-damaging alternatives, we would be ahead of where we are now. I am not the person to figure out exactly how to spend that $800 million or so. That was not even close to my field of engineering before I retired. You would not want my amateurish guess on that. We have really good engineering schools at U of M, MSU and WSU. I'm sure if they were funded with, let's say, $10 million - just 1/10 of what we spend on road salt every year - they could figure out how best to replace road salt. The right steps are for our legislature to find the political will to replace road salt, and then fund the study to get sound answers, and then follow the recommendations of the study.

Kevin Grand
Mon, 01/23/2017 - 5:26am

So, if the take-away I'm getting from this is correct, stop using road salt now and just find a solution later?Because of JIT, I don't see any auto manufacturers being too agreeable to this when they need to shut their plants down for several days at a time because they did not not have the parts they needed to complete assembly. And I highly doubt that the UAW is eager to sign off on having their member not getting paid due to a several day long "snow day".I don't see people dependent on medicines being delivered in a timely manner (i.e. doctor's offices, pharmacies or hospitals) being too agreeable to this because the medications they needed were delayed due to impassable roads. And if those same people begin to expire because of lack of medicine, the lawyers will be having a feeding frenzy over that.I don't see consumers being too agreeable to this when their local store has bare shelves for over a week at a time due to the weather. Even after the roads are made passable and deliveries are able to resume, it will still take several days worth of deliveries to completely restock just that one store alone due to interruptions because of the weather. The wider the area the storm affected, that time estimate will just increase geometrically. The capacity simply isn't there in the supply chain to restock them any faster.Again, not a bad suggestion, but if you cannot account for all of the variable right now, it won't be going anywhere soon (no pun intended).

Art Myatt
Mon, 01/23/2017 - 1:17pm

The take-away you are getting is not correct. There are states that get by with little or no road salt. Why are you so attached to it?

Kevin Grand
Mon, 01/23/2017 - 2:27pm

I'm attached to it because I've driven in those states who do not use it and I've seen first-hand the effects when people cannot get around.The best examples that comes to mind was when Georgia was hit with a really bad snow storm about three years ago.They had NO means of effectively clearing the roads nor treating them. Because of that, everything was shut down for at least three days while they tried to not only clear the roads with whatever they could get their hands on, but also deal with the stranded vehicles who were stuck on the roads (that they were also trying to clear) during that whole time.If you tried going cold turkey treating the roads like that here in Michigan (or other Midwest states), you will be seeing a huge turnover in elected officials due to the fallout of that decision.

Sherry A Wells
Sat, 01/21/2017 - 3:01pm

An article in Bridge about bridges--how appropriate. Now that the issue is (again) raised, I'm sure Mr. Myatt or someone can do a follow-up or more about Mr. Grand's comments: the alternatives to road salt, buying locally to ease the strain on trucks, and transit to reduce the reliance on cars and roads,

Gerald Hasspacher
Sun, 01/22/2017 - 5:36pm

Nice job Art!

Bruce Brown
Mon, 01/23/2017 - 3:42pm

The street I live on - not a thoroughfare by any means - gets plowed AND salted. There's really no need for salt or even noncorrosive substitutes on my street. Think of the savings if instead of thoughtlessly salting everything, road commissions put a little more thought into it. The savings might cover a big chunk of the higher cost of less corrosive deicers. Saving on road repairs, as the article points out, could apparently more than cover the rest. And it's not like we have to suddenly get along without deicing. Why can't our road commissions just order the right deicer the next time they need some?

Barron Richard
Mon, 01/23/2017 - 3:43pm

This appears to be one of those (rare) issues that should be non-partisan. While possible immediate negative economic impacts need to be carefully considered, taking "salt-free road diet" seems to me a reasonable and prudent step given the largely invisible but nevertheless real negative impact of salt on both our infrastructure and our water. I am grateful to Mr. Myatt for highlighting this issue.

Tue, 01/24/2017 - 12:09pm

Road salt is a great case of regulator and environmentalist's selective concern. I cringe every time I follow a salt truck. Unfortunately where people are not expected to possess individual responsibility road salt is what you get.

Wed, 01/25/2017 - 1:33am

Mr. Myatt makes many suggestions that leave me to wonder how much is knowledge based and how much is to promote a point of view.I have known some engineers and they would not make statements, such as suggesting sink holes are being cause by 'road salts' without having research and shared/linked to that information.Chemicals are reactive, sodium is more reactive than magnesium and calcium, there are also many other factors to consider, the effective temperatures the melt the ice, how quickly they melt the ice, how effective they are with other materials such as sand and inhibitors. This article suggests that MDOT and the local Road Commissions are simply dumping cheap accessible 'salt' and that is misleading. From what I can tell those organizations have some of the same concerns that are mentioned in the article and have been doing research on the best blends to use in specific situations, and they include environmental impact in their selection and application.A bit of homework would show that the damage to cars has decline over the years by a significant level. In the mid 1950s it was so significant that a rust proofing industry [Ziebart] was created and for 20 years it was a standard add on feature for new car buyers, since then the changes in ice melting and car technology have all but made that a distant memory.

Ron Korzecke
Thu, 03/23/2017 - 9:51am

We lived near Houghton in the Upper Peninsula for four years and salt was not used on the roads by the County Road Commission. After thoroughly plowing the road, sand was broadcast over the thin layer of snow that remained on the road surface. I never missed a day of work in those years and don't recall a school closing either.