Why salt overuse is a persistent probem

Madison, WI, has been trying to reduce the use of de-icing salt since the 1970s.  Despite many sincere efforts, application of salt by the City, plus private contractors, has continued to climb...along with the levels of salt in our lakes.

Why is it so hard to control the salt problem?  Let's try to think outside the box, looking for solutions where they may be hiding.

Problems that defy solution

There are some long-term societal problems I call "Intractible Problems," because they have defied solution for centuries.  Now, I hope readers will forgive me for speculating above my pay grade.  I'm just trying to put the salt problem in perspective.  There are some things to learn about why "problems" persist without solutions.

Drug abuse: There is increasing evidence that biology is lurking behind addiction.  Alkaloid substances like nicotine and caffein are known to be attractive to animals like bees.

But then society steps in and makes the problem a lot worse.  The management guru and author, Peter Drucker, once observed that problems like drug abuse are difficult to solve in proportion to the number of societal groups that benefit from the problem:

1. Politicians get votes by taking dramatic positions against drug addicts, peddlers, or smugglers.  This circus recently reached new heights as boats transporting drugs are being blown out of the water by the US military, using aircraft carriers and guided missiles.
2. Journalists and authors boost their careers by writing sensational articles and books.  Lobbyists play a similar role in promoting positions.
3. Law enforcement officials owe their jobs to combating drugs and stoking fear.  They often get to keep expensive assets like vehicles seized in the course of enforcement. This creates more incentives to keep promoting concern about drugs.
4. Fearful or credulous citizens continue to consume the articles, vote for the politicians, and support law enforcement, despite much evidence that current policies aren't working. Citizens may not be benefiting, but they seem to enjoy reading and hearing about the fuss and may "feel" they have benefited by voting for politicians who stoke fear.
5. Drug companies: Purdue Pharma, developed and sold OxyContin beginning in the mid‑1990s, promoting them irresponsibly, leading to widespread addiction.
6. Doctors and pharmacies profited as they continued to make prescriptions available despite obvious signs the drugs were being misused.
7. Farmers in the US benefit from growing cannabis, while Afghans grow poppies to produce heroin and Columbians grow cocaine.  Chemical companies benefit from producing precursors for fentanyl.
8. Drug pushers, smugglers, and trans-national crime gangs.  In many cases, the criminals are protected by politicians or law enforcement.

Following Drucker's lead, we see at least eight groups are in benefiting from the current ineffective approach to drugs.  I'm not saying people in all these groups want the drug problem to continue (except for those who directly profit).  What I am saying is that many groups benefit from all the noise and churn involved, while their actions support those unproductive approaches.  No wonder drugs are such an intractable problem.

Guns 

This issue is similar to drugs in that many of the same groups are involved.  Substitute manufacturers of guns for the groups that produce and push drugs.  One difference from drugs is that guns are more political.  This leads to the rise of advocacy groups like the NRA which have been extremely effective in both promoting guns and backing politicians who protect guns.

One extremely sinister aspect of the guns is that, the more fear grows from gun violence, the more people want to buy guns to protect themselves.  It's a self-reinforcing spiral leading us back to the Middle Ages.

The problem of violent crime has much in common with both drugs and guns.

What's evident when considering these most intractable problems is that fear is a driving force.

Why salt overuse is a persistent problem

I call salt a "persistent problem" because it's not "intractable" to the same degree.  It's not as ancient as drugs or guns, dating mostly from the time when we started walking and driving on pavement that could become icy.

Before salt, people sprinkled sand or "cinders" (from burning coal) on the ice.  Then we switched to salt when the sand began to clog waterway and cloud the water.  Eventually, overuse of salt has become a worldwide problem in northern climates--with reports of corroded bridges collapsing in Italy.

There aren't nearly as many groups benefiting from salt.  But there are some...

• Miners and transporters of salt or other deicers
• Manufacturers of equipment used in spreading salt
• Journalists.  Most are well behaved, excepting a few (below)
• Lobbyists: see below.
• Retailers of salt
• Trial lawyers who sue in slip/fall cases
• Contractors who spread salt on private properties
• Merchants or landlords--want to protect their customers or project a "caring" image
• Citizens benefit when they use salt to clear sidewalks, avoid lawsuits, or prevent slips on their front steps. They "feel" safer when more salt is spread in public places. Public officials are strongly influenced by complaints about slippery roads from the public. 

Note that several key actors from drugs and guns aren't big players in the salt problem.  Politicians and law enforcement are well-behaved here.

But fear of slipping on ice, and of vehicle accidents, is a real factor.  It has become axiomatic that salt makes us safer, despite evidence that oversalting has created disasters.  When roads are salted, people drive faster, counteracting the safety from salt.

Region-wide snowstorms, or multi-car collisions on highways covered by patches of black ice get a lot of attention in the news.  One of the reasons for so much attention is that pro-salt lobby groups promote stories about the benefits of salt.  

Some years ago shortly after a widespread snowstorm, many news stories appeared about the enormous economic saving to the region because preparations had been made for the storm--preparations, including of course, salt.  These stories originated with a lobby group.  Now, salt is associated with protecting commerce during the winter.

Safety vs harms of salt

This calculation of benefits vs harms is nearly impossible for stakeholders: politicians, officials, merchants, and citizens.  One reason is that the data hardly exists.  

Attempts have been made to calculate the harms from salt.  Most commonly they mention the economic cost for degradation of infrastructure.  These include corrosion of pipes, bridges, vehicles, and other infrastructure.  

It's less common, and harder, to calculate the dollar cost of harm to the environment.  These include lost recreational opportunities, the dollar value of lost fisheries, and many more harms.  These calculations are extremely difficult because of the complex interactions between species, the myriad subtle way that species can be harmed. It's also challenging to translate these harms into dollar values.

For example, recent research shows that pesticides leached into water shorten the lifespan of fish-- but do so without noticeable declines in vigor in the younger fish.  Who would have suspected such a subtle effect?  (Not salt, but it illustrates the unpredictable effects of environmental contaminants.)

Dollar values of harm are abstract and boring--they don't gain traction.  

Visible vs hidden

Everyone can see with their own eyes that a salted sidewalk is less slippery, usually. 

I was working at a heavily salted sidewalk, crouching down beside it, sweeping up salt to measure how much.  A woman came along, walking her dog.  As she approached, she scooped up her dog to protect its paws from the salt.  Preoccupied, she didn't notice me till she was very close.  Then, slowing quickly, she slipped for a moment on the loose salt before regaining her balance.

People struggle to weigh the readily visible benefits of salt against the nearly invisible harms.  Bridges and parking ramps rust from the inside.  Pre-stressed concrete beams cease to function when the steel ropes or wires inside rust.  They are very hard to inspect.  There are metods for reducing corrosion in new structures (like coating the steel elements inside with resins), but these increase costs of construction.

Failure modes of bridges and other corroded structures can be hard to predict.  When the causes of collapse are found, corrosion from salt is often just one of the causes.  When the I35W bridge in Minneapolis collapsed, there were 6 contributing causes--corrosion from salt was one.

The primary cause was a design flaw.  The designer was dead, so he couldn't defend himself.  His "sexy" design flaw was a sensation, while corrosion from salt was ignored by most people.

In Flint, MI, 99,000 people, including 55,000 children, were exposed to potential lead poisoning with overuse of salt as one of the causes.  The same disaster killed 12 of the 100 people who caught Legionnaire's disease.  The causal relationship of this outbreak to salt took so long to uncover that, again, people didn't realize salt was one of the causes.

Slow and invisible corrosion is easy to ignore. It's easy to respond to citizen complaints by spreading more salt.  As salt levels in water increase, animal populations will first lose vigor, then decline gradually.  Eventually, ecological collapse will occur when a keystone species finally succumbs to salt. All these harms take decades to unfold.

The zombie beets

Uncritical journalists sometimes contribute to the salt problem while looking for local stories with an upbeat vibe.  Enter sugar beets, stage left, to much applause.

Sugar is produced from sugar beet in a few states, including Wisconsin.  Sugar is extracted from the juice, which must then be properly disposed of because it's effectively sewage.  If dumped to waterways, juice decomposes in the water, fertilizing it (toxic algae bloom), and creating a deficit of oxygen, which leads to a fish kill.

The story that keeps rising from the grave is how some highway department experimented with beet juice they got for free--spreading it on the highway instead of salt.  And it worked!   Upbeat and clever.

What you don't hear is how the sugar producer got to dispose of sewage for free.  This story was even mentioned by a Senator at the hearings on a salt bill that I recently attended.  You are sure to hear this story at nearly every public meeting on salt.

Why beet juice will never substitute for salt...

• Pollutes the water and could kill fish by depleting oxygen
• Fertilizes the growth of algae
• Juice won't be free if the idea catches on
• There won't be nearly enough beet juice to replace salt
• Harder to transport and store than salt
• Not as effective as salt on ice

Easy solutions for difficult problems

It's just human nature:  If there's an annoying everyday problem, and someone suggests an easy solution, people are suckers.

You see it all over the internet.  "Deer eating your shrubs?  Sprinkle coyote urine about."  "Danger of collision with dear on the road? Install an ultrasonic whistle on your car.  Mice or chipmunks a problem?  Spread coyote urine, or mothballs, or cayenne pepper, essential oils, and so on.  The latest: rats chewing the electronics under the hood of your car. 

These are real problems, but the solutions aren't.  False remedies persist despite being constantly debunked by real experts.  But neighbors like to offer advice, and merchants like to make money by selling items like urine that cost very little.

People think: "I don't like coyote urine, so I'll bet the mice won't either."  People will try anything once, provided it costs less than $20 or $30.

The salt fix for snow and ice is similar.  It doesn't cost much, it's easy to use and store, everyone believes in it, and it works--sometimes.  Then there's the fear of injury to yourself, and being sued by others. Slips and falls are a real issue--but that doesn't mean salt is the only solution.

To make matters worse, some of the alternatives to salt are counter intuitive.  For example, snow and ice waste away via evaporation, even at temperatures well below freezing.  It's called "sublimation," and it can be used to speed the disappearance of ice.  Almost no one has heard of sublimation.

Because of all the quirks of human nature I've listed, kicking the salt habit is going to be difficult.  It's going to take a lot of public education.  We should focus on the various groups who contribute to the problem.

The Future

Will it be enough to just reduce levels of application of salt?

Modeling salt as we do climate change.

Mitigating the damage from salt in structures will continue.

How fast will salt dissipate if application is reduced.

Societal attitudes towards salt

Salt is considered safe because we put it on food

Salt is a pollutant in Canada but not in the US

It's hard to change human behavior

Stages of a problem (who would have thought salt could build up)?

Alternatives to applying substances to ice (another article)

Think outside of the box

Three disasters caused by overuse of road salt

Testimony on Salt Safety in favor of WI Senate Bill 1019 

By David H. Thompson, Ph.D.  2/17/26 

  

We think of road salt as making us safer.  But its overuse has helped cause major disasters with many lives lost.  Because salt is often only one of several causes of a disaster, salt’s deadly role goes unnoticed.  I’m going to describe how salt helped cause three disasters. 

In 2014, when Flint, MI, switched the source of its water from Lake Huron to the Flint River, salt in the city's water soared eightfold.  Salt in the Flint River came largely from de-icing salt.

 

Poisoning in Flint, MI

Despite the increase in salt from the switch, to save money the city did not add a corrosion inhibitor to the water, as required by law. As a result, both iron and lead pipes in Flint corroded, causing leaks and millions of dollars in damage.  Most significantly, the corrosion exposed an estimated 99,000 residents in Flint to lead., including over 25,000 children. 

 

At the home of Lee-Ann Walters and her 3-year-old son, average lead levels were measured at levels sometimes exceeding the EPA criterion for "toxic waste."  

  

Lead poisoning was only the first blow from salt.  When iron pipes corrode, it causes a chemical reaction that destroys chlorine added to the water to kill bacteria. Without enough disinfectant in the water, Legionella bacteria multiplied in the pipes of McLaren Hospital, lining them with bacterial slime.  More than 90 people caught Legionnaire’s disease... Twelve of those people died.  

 

In Flint, excess salt was one link in a chain of cause and effect that led to 2 separate disasters.  Everyone has heard about the lead pipes.  Almost no one heard about salt's central role in the poisoning and the disease outbreak. It took a long time before the connection between Legionnaires disease and salt was demonstrated, so most people never realized salt played a role in the 12 deaths. 

 

Collapse in Minneapolis

In Minneapolis, salt contributed to the deaths of 12 people and injured 100 when the I35W bridge over the Mississippi River collapsed in 2007.  

The primary cause of the collapse was a design error that reduced the strength of the bridge.  Corrosion by salt then further reduced the structure’s strength. Rust added to the load by trapping debris and

moisture.  And rust covered bridge components so the design flaw wasn't noticed.  The final NTSB report noted four other contributing causes.

The lesson here is that millions of structures we depend on, from vehicles to bridges, are being weakened--and their safety margins reduced—because of road salt. 

 

Mall Collapse in Canada

Another salt disaster happened in the Canadian city of Elliot Lake in 2012.  The parking deck on the roof of a shopping mall collapsed, killing 2 and injuring 20.  The building had experienced decades of water and salt infiltration. A key steel beam supporting the parking roof had corroded to only 10% of its original thickness.  

 

An inquiry found systemic negligence, ignored engineering warnings, and long‑term deterioration. 

What seared Canadians was the muffled cries of trapped and dying victims, who could not be rescued for 39 hours. 

Rather than remembering the role of salt, most Canadians remember the negligence. 

 

The lesson from this event is how often salt damage is minimized and ignored.  

Overall, these events show that the damage resulting from salt overuse can be lethal because the damage is... 

• Complex, 
• Unpredictable,  
• Nearly invisible, and 
• Acting over a time scale of decades. 

 

These qualities make salt overuse easy to ignore. 

 

....................................... 

Sources 

 

How Michigan’s Flint River came to poison a city.  The Guardian, Jan. 18, 2016. 

 

National Transportation Safety Board (NTSB). “Collapse of I‑35W Highway Bridge, Minneapolis, Minnesota, August 1, 2007.” NTSB Highway Accident Report NTSB/HAR‑08/03. Adopted: November 14, 2008. 

 

Kimberly J. Browns. 2018. The I‑35W Bridge Collapse: A Survivor’s Account of America’s Crumbling Infrastructure. Potomac Books / University of Nebraska Press.

 

CBC News, Oct. 15, 2014. Elliot Lake fatal mall collapse comes down to 'human failure,' report says. 

What is black ice--and why is it slippery?

• Black ice is relatively smooth, hard, and clear.
• Packed snow eventually turns to black ice, especially when it rains, or when there's a thaw, followed by freeze.
• You must completely remove packed snow if you want to prevent ice buildup.
• Black ice is most slippery when water is present.   Then it can be very dangerous.  Applying sand to ice greatly improves traction.

Black ice on the roads is what sends cars spinning out of control.  On sidewalks with black ice, pedestrians fall without warning.  So what is "black ice," and how does it form?

This "black ice" formed by freezing of meltwater.  It looks bright because it's reflecting the sunset.

Black ice is no different from ordinary ice--except that it's more compact and has a smoother surface.  Here's how snow turns to black ice.

How to prevent sidewalk ice--without salt

.

Use the sun instead of salt!

Key ideas...

• Prevent packing during snowfall by clearing a narrow lane--people walk there, preventing packing elsewhere.
• Clear to full width by noon of the day following snowfall.
• Scrape remaining packed snow so light gets through to the pavement.
• Let the sun evaporate the rest (ice can evaporate without melting).
• Touch up daily--before leaving for work.

Removing packed snow prevents ice

Clear sidewalk snow without salt

Prevent snow from packing down...

because packed snow turns to hard ice in a few days.

Snow blowers make things worse, because they leave a layer of packed snow.

Use a shovel with a sharp edge (or an ice scraper) to remove packed snow. The sooner you remove it, the less the ice sticks to pavement.

Shovel a narrow lane as soon as you can. People will walk there, and won't pack snow on the unshoveled portion.

Now use solar power to melt the rest! 

To disappear, ice (or packed snow) does not need to melt. It can go directly from solid to water vapor, even at temperatures below zero! It's called "sublimation."

Ice does require energy to vanish without melting. You have to scrape the snow thin enough so light energy will penetrate to the pavement. Even with thin clouds on cold days, enough sunlight penetrates to make a difference. The ice will disappear in a few days, depending on temperature and sun. Touch it up before you leave for work... the sun will do the rest.

To prevent icy patches from forming when it warms up, clear to the edge of the sidewalk between snowfalls. This way, any meltwater sinks into the ground at the pavement's edge. You don't get icy puddles on the sidewalk.

With more pavement exposed, the sidewalk area gets warmer, helping to prevent new ice--and the next snowfall is easier if the whole sidewalk has been cleared.

Prioritize

You have to clear your sidewalk, but you don't have to shovel your driveway, at least not right away.

Work in stages to avoid fatigue, resting between. First the central strip of the sidewalk. Then scrape packed snow. Then enlarge the width of the path. Finally, clear to the grass and chip any remaining ice.

Check the weather report. If it's going to warm up, no worry to clear snow. If a long period of cold weather is coming, be careful to prevent packed snow. Salt doesn't melt ice at temperatures below about 15F, but the sun does!

Even on hills or steps, you don't need salt. Sand works very well. You can find it in city barrels at street corners. You can buy Yaktrax to make your shoes slip-proof.

Hope this helps! HAPPY SOLAR SHOVELING !