Shredded tire mulch: Soft and safe or dirty and dangerous?

This Eyewitness News report from July covers the controversy of shredded tire mulch on playgrounds in Duluth. Cory Kirsling, father of a Lester Park Elementary School student, has started a GoFundMe page to raise money to have the mulch tested “for heavy metals, VOCs, off-gassing and leaching, toxins and carcinogens.” His page notes, “a local lab will collect the samples from our school’s playground, and we will share the research with everyone.”


Nick L

about 9 years ago

I don't like the mentality that something COULD pose a risk therefore it SHOULDN'T be used until proven ABSOLUTELY safe ALWAYS.  It sounds good but it is an impossible threshold.  Test for what?  What is "safe?"  Who determines "safe?"  How long do you study before satisfied?   How do you study?  

Rubber is a safe substance.  Yes, the individual components sound scary but so do the individual compounds found in an orange,  or an Oreo.

Aaron C

about 9 years ago

Broadly addressing the issue as a "mentality" misses the context of such risk assessment, Nick L. While there are many products people use first and then more research and regulation comes later, shredded tire mulch on playgrounds is one risk where many parents prefer to see the precautionary principle applied. 

1) The potentially hazardous substances from scrap tires get on and into children at the playgrounds, where many kids spend time nearly every weekday for years.
2) The synergistic effects of multiple chemicals in the developing bodies of children is not well understood, so the number of school playgrounds with the mulch essentially is a real-world experiment without parental permission.  
3) There are healthier playground cover options also recommended by government agencies for their cushioning properties (e.g., wood chips, pea gravel).

It's not unreasonable for a parent to want their children to stay away from tire mulch. Nor, based on current literature, is it unreasonable for a parent to be comfortable with the material. Those who are comfortable are free to use the tire mulch for their backyard playgrounds, while public institutions should take the more cautious stance on children's health, especially when perfectly good alternatives are available.


about 9 years ago

Natural rubber itself is safe.

The problem is that shredded tires is not made from natural rubber. It is vulcanized rubber with additives to create longer lasting tread along with residue from the metal belts used to reinforce the driving surface. 

Not to mention anything else the tire may have run across during it's life as a tire, which includes antifreeze, oil products, rotting animals.... so on and so forth. 

The concern is well founded, we don't want kids playing in something that may be toxic to them.

Nick L

about 9 years ago

My concerns are bias and that critics aren't defining "safe."  

From the GoFundMe petition:  "Our hopes are to start a campaign in our area of the removal of this unhealthy material and to spread awareness in the community..."    That's bias. 

What's Safe?
One study:  California's Office of Environmental Health Hazard Assessment studied shredded tire in 2010 and found no danger.  (Safety Study of Artificial Turf Containing Crumb Rubber Infill Made From Recycled Tires...).   

The dad's test WILL find many things.  Because something is detectable doesn't mean it's present in enough quantity to do anything.  We can detect substances in parts per million/billion/trillion.  Being present doesn't mean it's in a form that can harm.  There is cyanide in apple seeds.  Our kids snuggle in polar fleece made of polyethylene terephthalate.

Nick L

about 9 years ago

AARON C - Good point.  "Mentality" was a poor choice of words.

Paul Lundgren

about 9 years ago

It's hard not to be sensitive to both sides of the issue, because most people don't want to poison kids and also don't want to replace perfectly good playground surfaces. Nick L. makes a strong point that if you go looking for potentially harmful substances you will find them everywhere. Obviously sometimes that harmfulness raises to a level of being a serious threat, but exactly where on the danger continuum we should start getting concerned is ultimately an opinion based on sometimes contradictory scientific findings most of us don't understand in the first place. 

So, it's fairly predictable that any testing that happens will produce results that confirm it's dangerous or not dangerous, depending on what you believed before presented with the evidence in the first place.

All that having been stated, I've got an inbox jamming up with details, so I might as well start posting them.

Cory Kirsling shared with me an email from Duluth Public Schools Property and Risk Manager Kerry Leider providing details on the playground materials.
The mulch used in our playgrounds is recycled rubber product. Our standard specified product is Rubberriffic manufactured by International Mulch Company. Find information at I have attached their test data they have cited to indicate their product is non-toxic. The testing was for heavy metals. I know this shredded rubber material is the best surface we have had for attenuating forces from falls and reducing head impact injuries when compared to wood fiber, sand, pea-gravel and rubber mats. I have not yet seen any of the science behind reports I understand are out there suggesting these materials are hazardous due to their inherent toxicity. I will be very surprised if there is any qualitative outcome or conclusion to suggest there is any toxicity hazard that outweighs the benefits like reducing injuries due to falls and impact on playground surfaces. If there is ever conclusive science and data relating to this concern, then I will expect the Consumer Product Safety Commission will advise against its use for fall attenuation on playgrounds as we are now using it. If there are other authorities advising this material should not be used, I am not aware of any and will look forward to seeing it and then determine what action the District will take in response. My own perspective consideration: As you know, rubber is a very common material. If you think about vehicle tires on the road, rubber is wearing on driving surfaces. When these tires wear, there is very fine dust created and is ever present on and around roads and vehicles. The rubber used in our playground applications is not worn like it is with tires creating larger amounts of respirable rubber dust. I do acknowledge that there is some rubber dust and other dirt that will at times become airborne as people use theses playgrounds. I don't have any testing in this regard, but I expect there is equal or less airborne rubber around our playgrounds than exists on our sidewalks or nearby roads. This rubber does not provide a good medium for growth of microbes that are the source of allergen for some people. Our old standard, which was wood fiber, was found to be composting and continuously being consumed by microbial growth and related decay action. Sand and pea-gravel can contain silica, a known and common health concern, and the dust created from those materials might contain this hazard not to mention the damage those materials caused us when they were brought into our buildings. The rubber that comes into our buildings is a nuisance, but I'm not aware that it is causing damage to our equipment or building surfaces. I hope this response helps to explain where the District is regarding these types of concerns raised with the district's use of rubber as a safety measure in our fields and playgrounds, and reasons for continuing to use these surfaces. We will continue to monitor the matter for authoritative conclusion or warning against the use of these materials as we are currently using them. Please be aware, similar to your school, we have received other communication or concern raised by parents at Lester Park and Laura MacArthur, and Homecroft in response to similar media representations on this subject and I have shared this same information with them.

Paul Lundgren

about 9 years ago

Below is the test info referenced by Kerry Leider above. It is for leaching only and is not a test of any mulch specifically used on a Duluth playground.


Cory Kirsling

about 9 years ago

I have read the comments. And all make good points. Am I biased? Yes, It is my son. What I can tell you that I know for facts is this.
My son was coming home covered in a black dust. He would complain of headaches, sore throats, stomach cramps. I thought, maybe allergies, too much sun, didn't drink enough water etc.

The dust got worse. His clothes would be stained. It would not wash off them. We would have to scrub the dust off and it would smear like it was oily. After baths he would blow his nose and it would be grey and he had black boogers. And still I waited. We would find the mulch all over the house, it clung to everything.

We would think playing hard. See, my son is the kind of kid that does not complain, drinks from the hose, brown skin all summer, red faced in the winter, crashes his bike, jumps up and says “I'm ok. It’s just blood.”

And I'm proud of that.

We would go to the playgrounds, but not that often. We do other things, head to state park, camp, bike rides, Nerf gun battles, ect., and no issues no complaints. But when we would pick him up from school or key zone in the summer especially when it was hot out, he would state it again headache, sore throat, stomach ache. I asked if he had problems with other kids? I thought nerves. He said no. We checked in with teachers, staff. No jack is well liked.  

I never put it together. I would get out of the car to pick him up and you could smell the playground. That same smell was on his clothes.  The dust on all the kids faces. The heat from the mulch hot to the touch.

Then one day he came home covered in the dust and I mean covered. All the complaints.

I asked him, were you rolling in the mulch? His reply, “no.”  He said it’s really windy and the dust on the playground looked like black tornadoes. My stomach kind of dropped.

We cleaned him up had dinner, played, then books. Put him to bed. I was really bothered by his statement.

I was talking to my cousin from Chicago. I tell him my concerns. He jumps online and sends me some info. He says have you seen this about the rubber mulch or crumb rubber? No I haven't, I start reading.

I did not know like many parents that the mulch was made from tires. So I started reading and reading. I could not find that much information. One study stated it was fine, others stated it was not fine. And so on.

My wife and I wrote to the school and received responses, but were passed from person to person. We got a response from Kerry Lieder, the above letter. I wrote back and received no response. I really dug in and started reading. Here’s a short list of some of what I read.

Occupational exposures in rubber manufacturing industry (IARC working group)
St. Louis county solid waste ordinance
An a assessment of environmental toxicity and potential contamination from artificial turf using shredded or crumb rubber (Andea consulting)
Tire derived flooring chemical emissions study laboratory report (Cal recycle)
New York recycled tire and rubber product sellers (Empire state development)
Bandon parks and REC committee meeting notes regarding play ground tire mulch
Public playground safety hand book (U.S. consumer product safety commission)
Childhood blood lead case management guidelines for Minnesota (MDH)
Artificial turf (Environmental and human health inc.)
Review of the human and ecological safety of exposure to recycled tire rubber found at playgrounds and synthetic turf fields (Cardno Chem risk)
Impact analysis for the proposed carbon black manufacturing NESHAP (EPA)
Standard specifications for impact attenuation of surfacing materials within the use zone of playground equipment (ASTM)
Injuries and deaths associated with children’s playground equipment (Consumer product safety council)
Fatal pediatric head injuries caused by short distance falls (John Plunkett M. D. )
Brain Injury Australia policy paper for concussion in sport

And many more. I think that gives you the idea. To say I became obsessed is putting it mildly. What I read disturbed me. The information presented was either not finished or ran out of money or was made out of many reports put together, or no actual lab tests were done.

Every study, good or bad, said the same thing (more research needs to be done). No one could answer long-term effects or effects when you combine multiple chemicals together.

Also no answers on what is an acceptable level of chemicals.

We asked our son not to go on the playground anymore. His symptoms stopped! We felt terrible doing this. Every time I dropped him off I felt anxiety for him. I was sad for him. My wife would reassure me we were doing the right thing. But I got to tell you I cried. At that point I said I have to do something. So began the odyssey before us now.

I tried talking to parents, posting things to Facebook. I even posted a chemical a day on Facebook. What it was, what it was for, what it did to the human body. It was ridiculous.

So I hit the media and along the way learned more and more. I started the go fund me account to get testing done. I did not need testing done my mind was made up. But the district does and what they want will cost tens of thousands of dollars. It is not going to happen. Then the media, all I am going to say they got the word out. I could do without the sound bites, cuts in the middle of statements, and fear tactics, although the same could be said for me. Through this the worst part I wasn't paying any attention to my son. Who I started doing this for. The one person who has taught me more than anyone.

He once asked me, “Dad do you know what’s past outer space? No I said, what do you think? Time, and past that is God!” He blows my mind! 
So I got others involved. Up came the petition, Facebook page, meetings with school board members. PTA etc. People who were not calling me back before now were. That brings us to now.

Things I have learned:
No one knows much about this stuff. And that disturbs me.
They stop taking tires in landfills for three reasons. Space, water getting into the tires creating bacteria and bugs, and they leach because they are too toxic.
The government did not know what to do about getting rid of them (two million tires a year get thrown away)
Not very many tires have natural rubber in them (it’s too expensive)
Tires are made from nasty stuff. Benzene, lead, carbon black, PAHs, etc., etc., etc.
The EPA and U.S. consumer product safety council have backed away from their recommendations and state they really did not recommend the product in the first place.
The studies done by the EPA were poorly done.
The EPA states kids should wash hands after playing in them and definitely before eating and if they make their way into your house you should remove them.

The toxicologist I have been talking to asked me. Can you smell the playground (yes) then there off-gassing. One of the reporters got out of her car and I said can you smell it? She said, “is that the smell from the playground?” “Yes” I said. Wow I can smell it from the parking lot. 45 minutes later she said she was getting a headache. (That never made it on the news.)

I once took my laser thermometer and tested the playground mulch. It was 78/80 degrees outside sunny. The parking lot pavement was 123 degrees. The mulch was 145 degrees.

You see the dust in and on the kids. They are breathing that stuff in.

The claims about the mulch are much unproven for injury, and certain claims from the companies are lies. They market the mulch toward kids and playgrounds with names like Rubberific, but when you order the same mulch on the playground it comes in a bag marked garden mulch (turf council and others are being sued for this by PEER) that’s part of the reason they get around certain safety aspects.

In 1976 there was a law put on the books about chemicals. It states: It is the consumers burden to prove something is hazardous or harmful when it comes to the use of chemicals. That is why tire companies don't have to tell you what’s inside their product.

The test given to the district on the mulch is useless.

Will the test we are doing show chemicals in the mulch (yes) because that’s what’s in the mulch and what we are looking for. The school district did not tell members of the PTA what the mulch was made out of they just said it was rubber. Several said they would have fought not to put it down. Several teachers, janitors, and maintenance members have stopped to thank me and said that they hate this stuff and they want it gone. That they too, see the dust on the kids. I’ve been thanked for doing what I’m doing.

Are there many communities banning this product or removing it? Yes, more and more every day. I am sure there are things missing and I know I did not put every detail. I’m tired.

Do I believe that this stuff is harmful? Yes. Has it been scientifically proven? It depends on who you talk to. But I don’t think it’s worth the risk of waiting.

I love my son with all my heart, and there’s no other love that a parent has like it. If that make me bias, call it what you will if you need to call it something, but it’s my opinion and I’ve done my reading and I’ll continue to do so.

Cory Kirsling

about 9 years ago

I was tired when I wrote this the law suit that peer filed is against the epa


about 9 years ago

I think people need to talk to the adults supervising the kids on school playgrounds. I know two who suffer from severe sinus/allergy issues ever since the playground they work on 2.5 hours a day contained the rubber mulch, and gets worse every year.  

What are the studies on what happens as this stuff degrades?  

Not every school playground would contain the same samples of mulch since they were all built at different times.  And there is no telling how long the mulch sat around or was manufactured before ending up on the playground.  

Processing of the mulch will have changed as time moves on.  What was used to process it one year might not be part of the process other years.  

And last, but not least, if a majority of parents do not want this rubber mulch, the schools should not continue to support it's use.  However, if the replacement material that is acceptable to the parents who want it replaced costs more money, we will need to fund this replacement material with money that needs to be raised, as it is not in the budget of the schools right now.  

There is no perfect material to be used.  However, there is material that is natural out there, and should be considered.

Paul Lundgren

about 8 years ago

Cory Kirsling informs me that, as a result of the successful Go Fund Me campaign,  samples were taken directly from the Lester Park Elementary School playground on Sept. 3. 

"They were taken by a third party on request of Kerry Leider, the safety director for the school district," Kirsling wrote. "He had many conditions for the sample to be taken. Also he wanted to be present during sampling. We notified him of time and day. Also answered questions he had about the lab, etc. He did not show up for the sampling."

Kirsling said the sample was sent to Legend Technical Services, an EPA-approved lab in St. Paul, where it will be tested for volatile organic compounds, polycyclic aromatic hydrocarbons and heavy metals. 

A full report should be available next week, Kirsling said.

Paul Lundgren

about 8 years ago

In the meantime, for what it's worth, below is a 2001 material safety data sheet for the same brand of mulch used at Lester Park Elementary's playground, but not from a sampling of the actual mulch used there. 





Paul Lundgren

about 8 years ago

No word yet on the results of the test on the Lester Park Elementary mulch. For now, here is some generic literature from the Children's Environmental Health Center.




Paul Lundgren

about 8 years ago

Duluth News Tribune: Duluth School Board votes to replace rubber playground mulch

It is estimated to cost between $300,000 and $400,000 to replace the mulch. Some parents are advocating that it be replaced with an engineered wood product. Federal agencies and the state of California are undergoing comprehensive studies to determine the toxicity of crumb rubber used in athletic field infill and rubber playground mulch. Long-term effects of the chemicals found in the recycled tire rubber aren’t known, although limited studies haven’t shown elevated health risks. Board members have said they want to be proactive in protecting young children.

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