2/20/26

De-icing salt survey at 3500 University Ave, 2/20/26

 DRAFT        DRAFT        DRAFT        DRAFT        DRAFT

This link displays all photos in order, with a brief caption.

This is the location of the University of Wisconsin Extension.  This facility is large, with numerous sidewalks parallel to streets and leading to parking lots.  All sidewalks had been salted this morning, but there was no evidence that the parking pavement had been salted.

I spoke to the Building Manager, Ms. Stevie Seltman, stevie.seltman@wisc.edu., whom I met while sampling.  She knows the site is oversalted and has complained.  She said she would file a complaint with building inspection. 

The contractor salting the sidewalks is Maple Leaf.  The parking areas are salted by a different contractor.  The contracts for salting are managed by U.W. Groundskeeping, which does snow removal for the central campus.  Contractors salt at 3500 because this location is separate from the university, but U.W. Groundskeeping still controls the contracts for work at 3500.  If there's ongoing snow or another problem, the Custodian at 3500 may become involved.  So, there are 4 entities who may be involved with snow and ice removal at 3500, but the Building Manager has control of only the Custodian, who is rarely involved.

Weather

Conditions for sampling were near ideal because...

  • Foot traffic here is very low.
  • Concrete is smooth, uniform, and new.
  • Pavement had been cleaned of salt by rain. 
  • Light snow triggered the salting, but snow melted before sampling.
  • Meltwater dried before sampling.
  • There was probably too little wind to blow salt off the pavement.

Leading up to the survey was moderate rain or several hours on the evening of 2/19, followed by temperatures dropping below freezing and about half an inch (or less) of snow. The rain ensured that all prior salt applications had washed away.  Salt stains I had noticed on previous days were now gone.

When I arrived at 1:09 pm, all show on the pavement had melted, although there were a few small patches of snow on the grass.  The areas of pavement with more than light salt were still damp (dark in tone) but quickly dried within an hour or two.  Wind was 10-15 mph, probably not enough to blow salt from the pavement, and about 1/3 of the salt was lightly adhering to the pavement anyway.  There was some salt off the pavement, but it's probable this wasn't caused by wind, but by bouncing/scattering when applied.

Overall distribution trends

Salt distribution along the sidewalks is highly non-random or clumped.  Some squares get barely any salt, while others get 3 times or more amounts of salt.  I took many photos showing half or more of all the pedestrian walks.  There was even one salt spill in the back containing multiple small piles.

Thel pattern of salt distribution suggests "sowing" by hand or from a scoop.

Besides clumping, another visible trend was for salt application to be heavier towards the entrances, on the one stair, and on other areas of concentrated traffic, such as where sidewalks meet the streets.

Significantly, I could see in numerous places where the salt had spilled over onto the lawn or shrub beds, within a few inches of the pavement.  I took a few photos of the spillover but made no attempt to quantify how much or how far the salt had strayed.

How much salt was dissolved by meltwater?

I don't believe there was enough snow--with resulting meltwater--to significantly reduce the amount of salt I could see or collect.  There were just a few places where salt was absent, with salty footprints next to the bare spots. This combination,--no salt plus salty footprints--indicates the no-salt areas had been shallow puddles that were now dry.

There were a few conspicuous white shoe prints on the pavement, evidence that while the snow was melting, one or two people had stepped in salty puddles, transporting some salt from heavily salted areas.  Except for where the footprints originated, there were no salt stains on the pavement to suggest significant dissolution or aqueous transport of salt off the pavement.

However, the salted areas remained slightly damp (wet) for an hour or so after I arrived, so a small amount of salt could be distributed in a fine solid film on the concrete surface or have been absorbed a short distance into the concrete.

In two places where I removed salt, about 1/3 of the salt particles were lightly adhering to the pavement, but I was still able to use the dust bin to easily scrape all particles towards the center for final collection with a fine brush.  This "adhesion" suggests a small amount of water surrounded some particles, then dried--indicating partial solution of these particles. But it was probably not enough to substantially reduce the salt collected.

Quantification of salt at 10 sample sites

Photos show the context of all sample sites, plus verticals and closeups of the sites.  For each site, I used P. Gascoyne's photos (calibrated by volume), trying to match the pattern I saw on the pavement to the pattern displayed in the photos.

The sidewalk concrete at this location is relatively new, light in tone, and uniform in texture, making it a good location for comparing photos to pavement (except that the light tone minimizes contrast with salt).  Foot traffic is light (about one person every two hours), reducing any pulverizing or dispersal of salt by feet.

In selecting sample locations, I selected places of heavier salting, which were found on all walkways.  Sites were selected in part because they were close to my vehicle.  I did not seek out the very heaviest clumps of salt.  So I feel the sample locations are broadly representative of the many spots where a handful of salt landed.  But not representative of salt in between these "landing spots."

For each spot, I picked a "volume" of salt from PT's diagram that I thought matched best.  Then I picked a "volume" I thought matched second best, contained in parentheses.  I found myself using how many particles touched as one helpful cue.  I did note that PT's photos did not seem entirely random, as if he had used his fingers to redistribute particles, leaving channels without salt (tracks made by fingers?).  This apparent nonrandom distribution made it a little harder to compare photos to pavement.  The third number for each spot is the weight of salt collected, and the fourth number is the volume of salt collected.

The photos below show each sample spot.  For scale, use the width of the clip board, which is XX in. (inside the rounded corners).  Sites where I swept a sample have a blue template 12 inches square.  The salt was collected by sweeping with a soft brush towards the center, then using a plastic dust bin to scrape sticking particles towards the center. Finally, I removed all gathered particles with the brush sweeping repeatedly into the bin.

#1















#2


#3


#4



#5


#6


#7


#8


#9


#10



Conclusions about methods

  • When refining methods, it's important to select the right location and weather (see above).
  • Placing a 1 square foot template around sample is very helpful for documentation of where and provides standard dimensions.
  • Standardization of method is important.  As I continued sampling, method got more reliable--and best with blue template.

2/18/26

Why salt overuse is a persistent probem

 DRAFT        DRAFT        DRAFT        DRAFT        DRAFT


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


Lobbying groups for salt from CoPilot

The Salt Association
A UK‑based but internationally influential industry group that represents major salt producers and promotes the use of road salt for winter maintenance. 

They publish pro‑salt messaging such as emphasizing that de‑icing salt is “non‑toxic,” “cheap,” and naturally diluted in the environment — classic industrBottom line
There is no single U.S. national “road‑salt lobby” in the way there is for oil or pharmaceuticals.
But the two groups that most clearly promote de‑icing salt use are:

The Salt Association (international, industry‑backed)

National Coalition for Open Roads (NCOR) (U.S., pro‑salt advocacy)

If you want, I can map out the major salt producers and how they influence policy, or contrast these groups with environmental organizations pushing for chloride reduction.y‑advocacy framing. 

In North America, the closest equivalent is:
The National Coalition for Open Roads (NCOR)
This group advocates for increased use of domestic road salt, arguing that salt is essential for winter safety and that up to “90% of winter accidents can be prevented with proper application.”   
Their messaging strongly aligns with industry interests.

Other groups that indirectly promote road‑salt use
These aren’t lobbying groups per se, but they support or standardize salt‑based winter maintenance:

Clear Roads Consortium
A U.S. research consortium of state DOTs that develops best practices for salt and brine use. It does not lobby, but its work supports continued salt use. 

Salt producers and distributors
Large companies in the de‑icing market (e.g., Compass Minerals, Cargill Salt, Morton Salt) often participate in trade groups or fund research, but they do not operate a single unified U.S. lobbying association.

Bottom line
There is no single U.S. national “road‑salt lobby” in the way there is for oil or pharmaceuticals.
But the two groups that most clearly promote de‑icing salt use are:

The Salt Association (international, industry‑backed)

National Coalition for Open Roads (NCOR) (U.S., pro‑salt advocacy)

If you want, I can map out the major salt producers and how they influence policy, or contrast these groups with environmental organizations pushing for chloride reduction.

De-Icing & the Environment - The Salt Association

https://saltassociation.co.uk/de-icing/de-icin  .....


www.ncfor.org

American Salt for American Roads - National Coalition for Open Roads

https://www.ncfor.org/american-salt-for-ame   ...........

Materials: Deicers - Clear Roads

https://www.clearroads.org/materials-deicers  ...............









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 disastersalt’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.

 

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 thpoisoning 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. 

 

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 strengthRust 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 reducedbecause of road salt. 

 

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 negligenceignored 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 both dangerous and 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.