Hi people, first sorry for my English (I'm from Brasil). The deal is, having read some stuff about toxicity of tires, and that it should not be used for producing edible vegetables because of it's leaching effect on the soil and water; or even studies concerning dangerous uses of rubber crumb on soccer fields and playgrounds (check this for more info: http://www.plasticfieldsfornever.org/turf_report07.pdf).
Considering all this info, i would really like to understand if some uses of reused tire are really interesting, such as using it for leveling the ground, burying it for ecological sanitary uses or for building house walls with it. Any info you know about it, and if is there a conclusion on whether there is a safe use for reused tires, will be very welcome!

Hi Gabriel. Welcome.

The main issue with tires is offgassing. Basically, they weather like many substances. Also, UV radiation makes them break down, and their volatile organic compounds are released into the air.

Essentially, the less they are exposed to oxygen and the elements, and the more stable the conditions in which they are used, the slower they will weather. So using them in an earthship is better than using them out in the sunlight, because rammed tightly with earth, stacked, and cobbed over, they are kept out of the sun, surrounded by thermal mass that takes time to change temperature. Unless an air and water-tight membrane is used, though, as cob does let air and moisture through, the rubber of the tire would continue to break down and offgas its VOCs into the house envelope.

So yes, tires are not really good for your health. If there are other materials around, they are your better bet.

For structural materials, I would suggest rammed earth or compressed earth block, although the former requires much less in terms of specialised equipment, simply most of what you'd need for pouring concrete and tamping earth.

The idea of using tires for other purposes isn't a new one, and has resulted in some embarrassing and costly environmental mistakes. The technology now exists to turn tires into fuel. Apart from recycling the rubber into seals for machines and, I don't know, canning, converting them to fuel and burning them cleanly instead of pumping more petroleum out of the ground is probably the most environmentally friendly thing that can be done with them.

Tires are not safe for health or nature, in my opinion. Just smell them. If being in a hot room with a bunch of tires isn't appealing to you, do you think being in a shelter made out of them is a good idea? What causes the reaction that makes you want to get away from such types of specific smells? Could it be that your senses are trying to tell you something, much in the way that our ancestors' senses told them that human feces were best kept away from food and sleeping places?

-CK

Welcome Gabriel!  Your English is wonderful!

Gabriel Lavinsky wrote:Considering all this info, i would really like to understand if some uses of reused tire are really interesting, such as using it for leveling the ground, burying it for ecological sanitary uses or for building house walls with it. 

Used tires make really good beehive stands (when positioned flat).
They are really strong and indestructible, relatively light, easy to move around, and they are capable of holding large weight (especially when the metal rim is inside).
The best part - no construction is needed.
Just toss is down and level - done.
Optionally, place some wood onto the tire before setting a hive.
Or set 2-3 tires side by side, place long boards on top of them and then set your hives.
If care, you can even paint those tire hive stands; up to you.

Every time I see a used tire, I collect it and use in my bee yards.
I need MORE used tires!

I think that Chris covered it pretty well. Using tires in gardens is kind of like using old motor oil on fence posts and putting them on the ground--a topic i know Paul loved discussed on permies (wink wink)-- it probably works but it is not good for the environment and is not permaculture. Using tires in construction is probably not the greatest thing for breathing 24/7--this can be mitigated with proper sealing and so forth, but there are so many natural materials to use doesn't seem worth it. The recycling is great, and although tires can now be recycled for better purposes as chris said, most of them probably are just ending up in landfills with absolutely no secondary purpose. Ultimately for home building, I think it is less a healthy earth issue and more an issue for personal health. Great topic.

Hi Gabriel. Welcome to Permies :)

Chris covered most of it, but I'll add in a little bit. I was a landscaper 5 years ago, and a company had only just started up which took old tires and remade them into landscaping products. Rubber pads, edging around lawn, crumbs etc. Remember that tires are made from Synthetic Rubber, so they have similar polymers and other chemicals that'd you find in plastics.

My experience while handling the products:

The crumbs were horrible and they literally had their smell even after a year of being used as "mulch". I'm quite sure that they were actually hurting several flower beds because they absorbed far too much heat and cooked the topsoil - think of how hot a tire gets laying on the ground on a 27'C day. They even had little bits of metal wire from the tire sticking out of them occasionally.

The edging and walking pads had no metal and didn't have any smell to them. I assume they melted tires, filtered them a bit and then put the liquid into a mould. This would mean a lot of the chemicals, such as the ones that cause off-gassing, would be reduced while being produced. But then again, we have to think about how much energy is going into the process of recycling this product aswell.

---

Personally I have never reused tires. I'm not sure if it's possible to use a product in an environmental manner when it is leeching chemicals and giving off gases for long periods of time. I am reminded of a geoff lawton quote, referencing extreme situations and poorer countries: "In these situations it's better to eat dirty food than nothing at all" (paraphrased from something about making a garden with fly-ash cinderblocks)

In order to burn tires properly to produce energy several additional steps are required:

a baghouse to capture particulate matter (such as mercury), carbon injections to absorb heavy metals, dioxins and furans, and the addition of lime to neutralize acid gases. Computer systems closely monitor pollutant levels to make sure they remain as low as possible.

Then there is the problem of what to do with those collected pollutants, but out of all the possible scenarios, burning them in efficient generators is probably the best long-term option.
 
If your only options were to reuse the tires or see them go to the landfill to be burned, the choice becomes obvious to get them away from the landfill. Permaculture most times revolves around making the best immediate choice rather than the ideal choice.

---

I will briefly add, not with the intent to create a new discussion, that I see recycling(as an industry) potentially turning into something not so good. Industry growth in this area is usually related to an increase in waste products, which is most times a negative for society as a whole. The 3 R's, in their specified order: Reduce, Reuse, Recycle.

Reducing the amount of tires needed is more critical than figuring out how to reuse current waste tires.

Wow, thank you a lot for all replies. Glad to see my intuition was right, this is a group for a good debate. Thanks for the warm welcomes too!

So, as Chris pointed, the dangers of it are pretty much off gassing. However, I admit I'm still not too sure about the leaching effect. The researches I looked upon don't show a clear final result, but usually say that there is gradual leaching of zinc and some potentially toxic elements into soil and water. I think that some tire uses, some of which happen with ecological intentions, such  as using it for leveling the earth, or for making some sort of "natural" stair,  are not so ecological unless you take some actions concerning the bad effects of it. A solution I think would be some kind of plastic sheet between tires and soil, in order to reduce the leaching effect. But this I can just guess, and admit still haven't found a clear research showing, with clear measures, how bad it really is the leaching effect of tires on soil, how fast it goes, and if there is some way of reducing it to a safe point.

As far as I see, crumb tires are not a good option. Really, associated with cancer, and a huge list of toxicities, easy to inhale, off gassing, etc. I would not like to play soccer and have to breath this material.

I will briefly add, not with the intent to create a new discussion, that I see recycling(as an industry) potentially turning into something not so good. Industry growth in this area is usually related to an increase in waste products, which is most times a negative for society as a whole.

I think you are right Jarret, when you said that the recycling industry is making some things worse. Basically, it clears the faults of an industry that does not think ecologically, producing trash that the world is clearly not able to sustain. There is no way we should expect for all the tires to be recycled and then go to sleep in peace. The situation need dramatic changes, and I guess it is time for the industry to make the change. The tire material need to be redesigned, considering that a huge amount of these tires won't find a correct place for recycling. And also, proper recycling of tires is not easy. The correct transformation of tires in fuel does not seem to be cheap, so that in many places an incorrect transformation would take place. And that, apart from fuel (mostly used in cement factories) , the main end use for tires remains ground rubber (not good for health or nature).

I think we should be writing some kind of letter, or manifesting against the production of such a toxic product. But research is necessary, so we've already started that movement, at least.
On another hand, we don't need to stop reusing tires, but should know more about it's problems, and bring in the discussion about redesigning the product, which goes along with the permacultural struggle for a circular economy.

Thanks for the attention again, feeling more welcome to discuss these topics here. See ya

The conversion process I mentioned is a specific one. I wasn't talking about burning tires in an incinerator to power a heat engine for industry.

The process I referred to involves high heat and a retort to provide an anoxic (oxygen-free) environment to break down the tires into their component parts.

I am not sure of the particulars, but I believe the main end product was petroleum, probably diesel.

I think it would be better to convert tires to a liquid petroleum fuel, or to raw materials for advanced synthetics rather than to let them offgas and flake away on the soil or in the subsoil.

And wrapping rubbers and plastics in an envelope of more plastic and then expecting them to withstand stairway traffic probably won't work, in my opinion.

I don't think it's appropriate to use tires in contact with soil or water. I don't like the idea of using them earthship-style because the potential for them offgassing into my livingspace isn't worth the benefit of reusing tires.

-CK

The tires in Earthships are basically just a permament form or mould for rammed earth. But rammed earth holds up very well if you ram it in a temporary form, remove the form after a day or three, and keep re-using one form along the whole building. Also, using tires as your form forces you to make your rammed earth wall much thicker than otherwise necessary, just because of the size of the tires.

Earthships were a cool idea, but rammed earth is great even without tires. I've been living and working in two-storey rammed earth buildings since 1996, and I love how they are structurally, thermally, acoustically, and aesthetically and in terms of humidity. And a thousand years from now, I hope somebody is gardening in the soil recovered from our walls. Someone brought us the Earthship books while we were still building, and they were encouraging, but I'm glad we had already worked out our own revival of the local style of rammed earth, and innovated removable seasonal greenhouses instead of Earthship's permanent greenhouses.

I am almost beginning to think that Permies needs a FAQ document about the health and safety implications of using/reusing/recycling/upcycling old tires.  Although this question was initially about earthship construction, it has already branched into tire recycling generally and into using tires as garden planters (a practice that I myself make heavy use of).  We've had several people express opinions kinda facty-like and nobody has yet brought up Paul Wheaton's clearly expressed preferences on how he'd like to see the matter discussed in advancing permaculture education at this forum.  So I have added this thread to the recycling and gardening forums and I'm going to link a few relevant threads where this has been discussed rather heavily in the past.  Hopefully all that will help a bit.

First of all, some clarity: the original poster linked to a .pdf about a toxicity study involving a ground-up "rubber crumb" recycled tire product.  Virtually all of the quantitative information about the "toxicity of recycled tires" and other scientific information of that sort has focused on that product, which is an industrial material used mostly to make playing surfaces for children.  Because so much surface area of the ground up tires is exposed to air and water, leaching seems as if it may be a serious problem with the crumb material and it is absolutely the dirtiest possible way imaginable (except perhaps for open burning) to recycle an old tire.  I certainly wouldn't mulch my vegetables or children with that stuff.

Whenever the conversation turns to genuine recycling of old tires in their original or lightly modified forms (as in, no grinding, not much cutting or drilling) be aware of one thing: there is no science.  Nobody has done any.  If somebody makes a confident statement about toxicity, they are at best incorrect, or at worst, telling you a whopper.  Nobody knows.  Because nobody has studied it very much.  (Disclaimer: that I know of.  I haven't seen any studies.  No studies ever come up in these discussions.  The studies cited always seem to be pointing at ground-up tires, or tires in water.)

Some opinions offered in this thread are that old tires used for earthship housing construction "are not really good for your health," and "are not safe for health or nature."  Another poster has opined that using tires in gardens "probably works but it is not good for the environment and is not permaculture."  My own opinions run to the contrary but I've gone into those elsewhere; I highlight these here just to point out that we are swapping opinions.  In particular, what's good for the environment depends a lot on context; when I pull old tires out of a roadside litter pile and make it into a neat garden planter, I challenge anybody to establish a net environmental detriment.  Where you end up depends an awful lot on where you start!

As you might imagine, this has all been thrashed out in some length on Permies in the past.

8 years ago: Are tires safe to use in and around gardens?

Highlights:

paul wheaton wrote:The recycler/re-user in me conflicts with the organic in me.   But I've had tires offered to me before and in the end I always reject the tires. 

They just aren't inert enough for me.

But .... that's just me.

5 years ago: Big tires for "Keyhole-ish" design

Highlight:

paul wheaton wrote:
2)  My mission with these forums to gather knowledge about stuff far beyond organic.  I don't want to publish discussions on GMOs, herbicides or petroleum fertilizers - that's for other forums.  The use of tires is something that might be considered organic, therefore I will allow it.  but just barely.  And I do want the resulting discussion to strongly favor NOT using tires. 

3)  When I first started gardening, I really sucked at it.  But I quickly learned that I needed more soil.  And one of the things I did was use a big tractor tire and fill it with soil.  It worked awesome:  the rhubarb planted in it was HUGE!  It was about a year later that I started to feel uneasy about the tire and the potential toxins.  And a year after that that I started making plans to get rid of the tire.   And now I am adamantly against the idea of using tires in gardening.   Therefore, i cannot fault this path - I've done the same thing.  And I hope that folks coming to this site and reading this thread will come to the conclusion of not using tires in their stuff - thus avoided my past errors.

1 year ago: Are tire planters safe?

Highlight:

Nah.  It looks too vain when I quote myself, and besides, I disagree with Paul.  You gotta click through if you want to see why I think the benefits outweigh the potential toxicities.  And maybe in a few more years I'll be further down the path and saying the same thing as Paul, who knows?

This remind me of some thoughts regarding recycling that I wanna express:
I respect anyone when it comes to concerns on what to do with old tires. But.... for some people that seem to have this itch (right expression?) to reuse tires whenever they can, I gotta add: there is this great gap between the industry of production and the structure of the post-use of these products. Tire is one of the worst examples of it, it is useful and used all over the world, BUT we have not enough concerns from the producers on what to do with it, even more considering it will last more than 600 years decomposing, liberating toxicity as far as studies show.

So, big trouble, uh? How to solve it? Should we really be concerned about how to recycle it? If you are, good. But it seems more emergent to me to rethink the design of it, and even more, to remind people that recycling will not save the world. No way we can expect that. Recycle will help mend some trouble created by the actual crazy state of things, when we as global society produce a lot of stuff that we don't even want to know about after it is used, even when we know it is going to be bad for some neighbor country. In Brasil, we see tires specially in poor places, where they become home for mosquitoes and other plagues.

So, i think that:
if we just recycle, but don't bring in the critic (or concern) about the industry that produce  toxic material and have little concern about whatever happens next, we are giving a vote to a state of world where, as pointed earlier, recycling will make it worse, instead of making it better for the environment, both social and natural. If we really want this recycle thing to work, I think we should remember to bring in this critic, which we can attempt to resume it in the sentence: "OK, we are recycling, but this is not the solution, it is just a part of the immediate remedy. If we want to truly change this situation, we need to change the production industry, we need to redesign and consider the post-use right in the design of the product". I know many of you think like that, but here in Brasil I've been seeing many works with tires. Great (some), but many of them seem to bring the idea that we should be handling somehow this trouble, that we (common citizens) should find out a way of dealing with the tires we find out in the streets (without considering the great amount that get to the oceans), when it seems to me that it is more necessary to find out alternatives to the present state of tires.
But as we say here in Brasil, I'm just "problematizing" :P
Also that's the conclusion I've come to, to bring in these thoughts whenever working with reused tires. Not saying everybody should do the same

p.s: the FAQ seem a good idea. I also think that every discussion could have some kind of 'Highlights Table' of it, maybe done by some volunteer. Could make it easy for those who want to catch up info quickly. Cheers 

Gabriel Lavinsky wrote:"OK, we are recycling, but this is not the solution, it is just a part of the immediate remedy. If we want to truly change this situation, we need to change the production industry, we need to redesign and consider the post-use right in the design of the product".

Gabriel I just quoted one sentence from your post but really I am in agreement with the whole thing.  At least in theory, you are 100% correct.  It's just... I'm not recycling to change the world, I'm recycling because I am, by local standards, poor.

When I pull tires out of the waste stream (or, as I do more often, when I pull them out of the natural environment where they have been dumped by assholes as litter and pollution, because in this country there is a fee to put them in the official waste stream that many people prefer to avoid by illegal dumping) I am "solving" one immediate problem but I am not changing the world and in a way I'm even taking off some of the pressure on the producers of the problem.  I am also creating some pressure and problem for the future owners of the land where I put these tires to use, which is the biggest reason I'm not using them on a much larger scale.  That's something I've discussed with my wife in detail (it's her family land) and she's firmly of the opinion that I am creating net local improvements with the tires; this land is in terrible condition from previous abuse by oil and cattle interests so that's at least plausible. 

What's going on is that when I see this litter/pollution/waste at the side of the road and dumped on public land, I see a resource.  There's an ENORMOUS wealth of embodied petroleum energy and minerals in a used tire, taking the form of strong chemical bonds and great physical strength and durability that I can use for all kinds of projects, mostly planters and makeshift gabions (rock baskets to control erosion).  By local standards I'm not wealthy enough to drive past those resources and ignore them; and in fact, I'm not as wealthy as most of the people here on Permies who have the luxury of taking counsel of their concerns about toxins and deciding "better not take the risk".  These resources solve problems for me that would otherwise go unsolved; I don't have the money to buy equivalently strong building materials or the strength and physical fitness to build equivalently strong structures from the natural materials on my land by hand or the capital equipment (petroleum powered machinery) to assist me in doing so with the strength and fitness that I do have.  So I use them.

I do agree, though, that it would be a huge mistake to vanish the whole tire waste stream into reuse and upcycling without requiring the tire industry to assume more responsibility for the problem they are creating than they do now.

Chris Kott wrote:The conversion process I mentioned is a specific one. I wasn't talking about burning tires in an incinerator to power a heat engine for industry.

The process I referred to involves high heat and a retort to provide an anoxic (oxygen-free) environment to break down the tires into their component parts.
I am not sure of the particulars, but I believe the main end product was petroleum, probably diesel.

The topic of my thesis  was "technological, economical, and environmental issues of  scrap tires utilisation processes".
I'm a chemist by profession but environmental extremist by soul. 
For me the most scary way of scrap tires utilisation was creating a .....reef of them.
introducing  such a contaminant into such extremely fragile habitat made my soul scream.
The one who knows the chemical composition of tires already gets a thrill.
Most of the rubber mix additives are top secret technological and you must believe me those compounds are not the one you'd love to have in your soil.

And yes.. the most enviro friendly way of utilising them was pirolisis.
It allowed to regain at least a part of energy  of the tire production process.
The oil obtained  has a similar composition to heavy fractions from crude oil distillation thus after refination can be used as a fuel.
The gas is used as pirolisis energy source. The coke was considered  a waste.
unfortunately the process is not economically viable unless  the price of a oil barrel reaches 197$
therefore  most of scrap tires ends up exported to...Kuwait to be stored on the worlds biggest scrap tires landfill.
That got in flames a couple of years ago.
some ends in a cement kilns and we hope the cement producing plants cares about their stack emission.
  

I love how these topics go around and around and after 20 years the same guesses and assumptions live on and nobody seems to know about resources equally old.

Some actual research (whoever posted there's no science is incorrect) from University of Wisconsin, a compilation of a bunch of stuff, all under the heading "Use of scrap tires in civil and environmental construction" is here:
http://chbenson.engr.wisc.edu/images/stories/pdfs/Reports/UW-Madison%20Scrap%20Tire%20Reprints.pdf

There was one major report - probably included in this compilation, and I have a hard copy somewhere still I think - that was pointed to by the Earthship folks back in the day. It basically said that used tire material buried in the ground doesn't seem to leach much of anything and since it's buried there's no offgassing and no UV-destabilization. The use case was chunked up tires as part of a subsurface earthen fill and/or embankment material for civil engineering. Any buried tire application is essentially similar, unless there are also solvents in the ground that degrade tire material, in which case the tire is probably the least of the problems.

What might be of major concern is the use of tires on actual cars, where they are a major non-point pollution source spread all over the country and emitting whenever they are driven on, spewing out tiny particulates that move with the air and water.
So for anyone concerned about reducing pollution from tires, the place to start is cars. Forget that old tractor tire planter in Grandma's yard. Minor issue. Do something about all those cars!

What might be of major concern is the use of tires on actual cars, where they are a major non-point pollution source spread all over the country and emitting whenever they are driven on, spewing out tiny particulates that move with the air and water. So for anyone concerned about reducing pollution from tires, the place to start is cars. Forget that old tractor tire planter in Grandma's yard. Minor issue. Do something about all those cars!

I think the above statement sort of hits the nail on the head for me!

Well, we can all debate what may or may poison us all and the merits of recycling tires, bottles and so on, but reusing them vs leaving them all to rot in landfills and such seems like a no brainer to me.  I'm somewhat willing to accept the trade off. I do a lot of woodworking and have to accept that every time I use a new piece of wood to make something new from it a tree has to be cut down somewhere. I'm not in favor of cutting down every standing tree on the planet, but the wood has to come from somewhere.
Do I accept the bit of poisonous leeching if I'm building a new home vs using the many many alternatives? I don't know all the alternatives and don't have the time to research each and every single possible negative impact now or 50 years into the future.
How many foods have you ever eaten only to later learn about the possibility of getting cancer only to later learn it's healthy for you only to find that you're going to die anyway regardless of whether you eat it or not.. Ok, so you'll live an extra 15 minutes! It'll be the best 15 minutes of the last 16 minutes of your life.
The stuff released by tires IS GOING TO get into the air and water and soil if for no other reason than there are millions upon millions upon millions of them spun around at high speed all around town and the world every single day of every year and those little particles are all around us. At least inside of a wall those particles aren't being tossed out into the atmosphere at high speed  up and down every street from here to China and back..  It's probably worth the trade off if you're ok with that last 15 minutes not being as spiffy as you originally planned.

Its all good for at least the next 100 years.

John Schinnerer wrote:I love how these topics go around and around and after 20 years the same guesses and assumptions live on and nobody seems to know about resources equally old.

Some actual research (whoever posted there's no science is incorrect) from University of Wisconsin, a compilation of a bunch of stuff, all under the heading "Use of scrap tires in civil and environmental construction" is here:
http://chbenson.engr.wisc.edu/images/stories/pdfs/Reports/UW-Madison%20Scrap%20Tire%20Reprints.pdf

There was one major report - probably included in this compilation, and I have a hard copy somewhere still I think - that was pointed to by the Earthship folks back in the day. It basically said that used tire material buried in the ground doesn't seem to leach much of anything and since it's buried there's no offgassing and no UV-destabilization. The use case was chunked up tires as part of a subsurface earthen fill and/or embankment material for civil engineering. Any buried tire application is essentially similar, unless there are also solvents in the ground that degrade tire material, in which case the tire is probably the least of the problems.

What might be of major concern is the use of tires on actual cars, where they are a major non-point pollution source spread all over the country and emitting whenever they are driven on, spewing out tiny particulates that move with the air and water.
So for anyone concerned about reducing pollution from tires, the place to start is cars. Forget that old tractor tire planter in Grandma's yard. Minor issue. Do something about all those cars!

We have a winner. The guy behind earthips, Michael Reynoulds, looked into this a long time ago. Tires have a half life of something like 30,000 years when buried in a landfill situation.(one half life used=50% life remaining) There is no way to recycle them but you can re-purpose them. When they're shredded for playground mulch, they still get sun, freezing temps and high temps. That makes them break down pretty quick and then the nasties get in the soil/water. Burning them of course, is way worse unless. There is an industrial recycling process called tire pyrolisis https://en.wikipedia.org/wiki/Tire_recycling#Tire_pyrolysis

Currently, burying them is the safest option there is for tires. Burying them in landfills, they get mashed, mixed with other stuff, might stick out of the ground at times and will have rainwater flowing against them. Buried in an earthship, they're kept cool, dry and out of the sun. I don't know think a study of the half life of them in that case would result in. 100,000 years?

Meanwhile, you can make some cool looking outdoor furniture.

As far as out-gassing through the dry soil and whatever you coat your inside walls with, keep it fresh and crack free. I know some old tires guys that have been in the business their whole life and that's with dealing with stinky new tires and seemingly had no health problems at the age of 60 or so. 

Drive less and don't park your tires in the sun.

John Pollard wrote:

John Schinnerer wrote:I love how these topics go around and around and after 20 years the same guesses and assumptions live on and nobody seems to know about resources equally old.

Some actual research (whoever posted there's no science is incorrect) from University of Wisconsin, a compilation of a bunch of stuff, all under the heading "Use of scrap tires in civil and environmental construction" is here:
http://chbenson.engr.wisc.edu/images/stories/pdfs/Reports/UW-Madison%20Scrap%20Tire%20Reprints.pdf

There was one major report - probably included in this compilation, and I have a hard copy somewhere still I think - that was pointed to by the Earthship folks back in the day. It basically said that used tire material buried in the ground doesn't seem to leach much of anything and since it's buried there's no offgassing and no UV-destabilization. The use case was chunked up tires as part of a subsurface earthen fill and/or embankment material for civil engineering. Any buried tire application is essentially similar, unless there are also solvents in the ground that degrade tire material, in which case the tire is probably the least of the problems.

What might be of major concern is the use of tires on actual cars, where they are a major non-point pollution source spread all over the country and emitting whenever they are driven on, spewing out tiny particulates that move with the air and water.
So for anyone concerned about reducing pollution from tires, the place to start is cars. Forget that old tractor tire planter in Grandma's yard. Minor issue. Do something about all those cars!

We have a winner. The guy behind earthips, Michael Reynoulds, looked into this a long time ago. Tires have a half life of something like 30,000 years when buried in a landfill situation.(one half life used=50% life remaining) There is no way to recycle them but you can re-purpose them. When they're shredded for playground mulch, they still get sun, freezing temps and high temps. That makes them break down pretty quick and then the nasties get in the soil/water. Burning them of course, is way worse unless. There is an industrial recycling process called tire pyrolisis https://en.wikipedia.org/wiki/Tire_recycling#Tire_pyrolysis

Currently, burying them is the safest option there is for tires. Burying them in landfills, they get mashed, mixed with other stuff, might stick out of the ground at times and will have rainwater flowing against them. Buried in an earthship, they're kept cool, dry and out of the sun. I don't know think a study of the half life of them in that case would result in. 100,000 years?

Meanwhile, you can make some cool looking outdoor furniture.

As far as out-gassing through the dry soil and whatever you coat your inside walls with, keep it fresh and crack free. I know some old tires guys that have been in the business their whole life and that's with dealing with stinky new tires and seemingly had no health problems at the age of 60 or so. 

Drive less and don't park your tires in the sun.

You know that if you go hang out at a used tire shop (I've worked in the business) you'll find the most of the danger is from mashing your fingers, getting a tire blown up in your kisser and the like.  You probably won't find a lot of super health conscious types working at those places, but will find a lot of alcoholics and druggies .. That's not saying much for the industry. I've worked with hazardous materials most of my life and at 58 I can't say I'm too much more worse for the wear.. I have nervous ticks and other ailments, but most of them could be traced back to solvent exposure and slips and falls and other not so fun incidences..  I doubt that I'm going to die directly from whatever chemicals used tires might have put out.
I get it. Most people want to minimize the risk and for good reason, but at the same time we also have to find the scapegoats.
I painted in a spray booth for years with minimal protection and have the medical documentation to prove it, but my time with tires was probably the least of things that effect my overall health at this point in time.
The toxic release being discussed with tires is a relatively slow release compared with many other things I've been exposed to in my working life. If I had to rate it on a scale of 1 to 100 compared to the rest of the crap I've been exposed to it probably wouldn't reach the double digits. I kind of doubt it would reach whole number territory as opposed to say, shooting xylene based paint for 70 hours a week for 5 years with just a simple $35 respirator to breath through all day long.  
I'm not telling you there is no risk at all, but it's nowhere near the stuff many of us deal with every day on the job. I've been around welders who died as young men or went blind before their kids reached high school. I personally know two who died from lung cancer, but zero who have died as a result of used tire exposure.
It's up to the individual to determine the risk they're willing to take. As I get older I'm less likely to accept the risks, but I'm not working in a high risk profession any longer.
The risks are not nothing. They do exist so you have to weigh the risk against whatever possible gain you may have by using used tires to do whatever you might want to use them for. This is just my perspective.

I'm currently nursing my husband around the clock because of bladder cancer.  It's a disease that is caused by toxins that enter the body and end up sitting in the bladder as they are removed from the blood and are excreted into the urine as part of the body's natural de-tox system.  The urine gathers in the bladder and the toxins do their damage there before they leave the body.  It generally takes 25 to 30 years before symptoms start to show. In my husband's case it was toxins from the resins and dyes used in his business making fibre-glass boats 40 years ago, so I guess I should be grateful that I've had an extra ten years with him. 

Seeing that photo of chairs made out of old tyres made my blood run cold at the thought of any potential carcinogens transferring right through the skin of anyone sitting on them. 

I did a quick google of 'bladder cancer tyres' to see if there was a known connection, and I got a lot of hits!

This one might be the most poignant.

Widow Speaks Of Shock At Finding Out Husband's Fatal Cancer Was Linked To Career in Tyre Industry - the coroner ruled that his death was due to an industrial disease caused by his working environment in the tyre manufacturing industry which was contaminated with dusts, gases, vapors, fumes, and chemical byproducts to which workers can be exposed through inhalation and skin absorption.

Here are a few more links that showed up in my google search

Cancer risk in the rubber industry: a review of the recent epidemiological evidence

A case-control study of bladder cancer in the United States rubber and tyre industry.

Bladder tumours in rubber workers: a factory study 1946–1995 - the link seems to be time dependent somehow - google the title and try from the search results if it plays up.

As for using tyres - I agree that putting them to use, safely, might be the best thing to do with them. But handling them, living in houses built of them, making furniture out of them, growing food in them, letting kids play with them or sit in them, all seem like insane risks to me.

To me the absolute biggest take away from this discussion is we need to figure out how to structure our lives in a way that we do not need rubber tires to function. I am as guilty as most, I have a truck with four tires on it, but I want to figure out how to do without it.

Hi again. Well, concerning using tires underground: after everybody uses and then leaves the site, the tires will continue to disintegrate, and the risk of leaching and contamination of underground water will rise up with time, the speed of it will depend on the volume of tires used, and conditions of disintegration. This is obvious, since we are spreading a disposable full of toxic additives industrial product all over the planet (a very dangerous combination, plastic is another related issue).
To me, the fast we change into an ecological and circular alternative to the vulcanized tires, the best. Since I'm no specialist on the area, I can only gather my good sense, do some research and hope that more people see the danger of it and start moving towards a solution. But, please, no panic. Stress will not be a good guide.

Doing some wiki-research (and please, correct me if I have misunderstood something) I've found that, stepping some two steps back, and we have the origins of tires: created in the late 19th century, by Mr. Dunlop, the pneumatic was actually composed of a sort of rubber hose (rubber being a natural material extracted from the rubber tree, here in Brasil we used to export a lot of it until WWII). Well, this first tire could be used for some things, but as the car industry started to grow, they needed it to build more resistance to weight material, in order to impose the also crazy state of motorized transportation we have nowadays. So, remember: in its first state, tires were biodegradable.

The problem began when they started to combine this invention with another, which was the car based traffic system that was only emerging, and promising to connect cities and end up starvation, and other calamities. This is the modern age. The process used to enhance tires was vulcanization. This process brings a bunch of advantages to the tire, such as "good tensile strength and extensibility, it can return to original shape when the deforming load is removed, low water absorption", and some other cool things. Problem is, the most used method of vulcanization is the sulfuric method, which consists of accelerating the vulcanization process (needed for the resistance and durability desired) through the use of many additions, such as sulfur, zinc oxide, stearic acid, antidegradants, and others. I'm no specialist, I repeat, but I see the big problem lies somewhere in this part, through the process of sulfuric vulcanization and adding additives that makes tires such a toxic product.

What's the answer? I don't know, but we gotta close the loop, right? If it is to be disposable, tires technical parts should be easily separated from biodegrading parts and then be recycled in an economic functional way; also considering that these post-processes should work in any country, which would lessen the cost of sending tires to some country to treat it (and having the risk of having it burned just like happened in Kuwait video above). Don't know the answer, but maybe more people can add knowledge concerning this topic, so that we can start making the pressure needed to change it.
Related to the uses of tires concerning health, specifically, I've got a tire chair myself, I've made some using a simple technique (you can see some of it here: https://cinemobileblog.wordpress.com/2017/05/28/praca-de-central-carapina-270517/). After reading all these things, we have taken the caution of not exposing it to direct sunlight, and we have even covered ours with a kind of cloth in order to avoid direct contact with the hand-and-mouth (very common contact when you have tires furniture).

I use tyres as garden walls, I stack them to the desired height, I use tek screws as I build them to keep them connected. I offset each so the wall is a bit wider than the diameter of the wall.
Each column of tyres has exactly the same sized tyre so they feit together better.
Sometimes I fill the tyres as I build them up so water cannot collect in them to breed mozzies.
I have capped some with not fill for the same reason.
Others I have filled with dirt, not rammed its too hard.
Others I have filled with old bottles, rocks, building rubble I have scrounged,
I have kept some low, say 2 or3 tyres high and grown plants in them.
I reckon they are great and can be used in areas where any proven issues in the future will not be a problem.
I have seen some wound with mesh , and had either ferro cement or lime mortar plaster put over them.
I live in a dry climate and have carried out no tests what so ever on them.

I have used them as moulds for concrete blocks to go under shipping containers to create a good sized pad.

John Schinnerer wrote:. It basically said that used tire material buried in the ground doesn't seem to leach much of anything and since it's buried there's no offgassing and no UV-destabilization.

That's right. But the rapport you cited was pretty old.
And they didn't bother to do  long term experiments about influence of  soil microbial life on the product decomposition rate.
Once you ask Paul Satmets he will ensure you that fungi hyphae is a learning structure and learns how to produce new enzymes to digest any source of carbon it finds on its way.
I saw some YT video with where the oyster hyphae learned how to digest the cigarettes buts.
(chemically: it contains so many  PAH's that  decomposing it is a heavy task, nonetheless the fungus has managed.
When you take this under consideration I'd strongly discourage from putting such a potential source of Zn (zinc) into ground.

I was actually going to add something along the lines of what Jura just posted.

I would be much happier with the use of buried tires in the landscape if I could inoculate them with Oyster Mushroom spore before they were buried. I don't know if mushrooms would make unhealthily high levels of zinc bioavailable to plants, though. They seem to perform a more regulatory function than that.

Yes, they will break down slower if buried in the walls of a structure. But sub-surface dwellings have a long history of moisture problems. Water has ever been known as the universal solvent. It will get to the tires, and stuff will leach into the water table. Even in a case like a proper wofati, where you have that umbrella layer and a large amount of dry fill under it, the water table can still fluctuate.

If you've got dirt suitable for filling tires in the earthship manner, you have dirt suitable for filling earthbags, or perhaps even for making compressed earth block or rammed earth. I could see using tires to reinforce plywood forms for the ramming of earthen walls.

As to garden walls, I would probably want something more aesthetically pleasing. Barbed wire or cinderblock are prettier, and more aesthetically pleasing, and I am sure you could pull cinderblock out of a demo somewhere.

Really, I think tire pyrolisis as a stacked function of some other process is the safest way to reuse tires. I want that stuff as far away from me and mine, and my soil, as possible.

-CK

Chris Kott wrote: I don't know if mushrooms would make unhealthily high levels of zinc bioavailable to plants, though. They seem to perform a more regulatory function than that.

Well.. I  live in a ex-mine area.  I can recall in my childhood we were strongly prohibited prom picking up mushrooms  in the nearby forests.

What I understood now is that the frutification of a fungi may contain a high concentration of heavy metals once the "intelligent network" decides the element is harmful for the rest of hyphae  it transports it to its most remote ends and fruits. (kinda kamikaze)
Once the soil is healthy (and mycorrhizal fungi are present) then conditions from the belows quotation (from a soil bioremediation book) may apply.

Arbuscular mycorrhizal fungi (Glomeromycota) are ubiquitous soil microbes considered essential for the survival and growth of plants in nutrient-deficient soils. They are frequently seen as a tolerance mechanism of plants in highly metal-polluted soils. Mycorrhizas constitute a bridge for nutrient transport from soils to plant roots. At higher soil metal levels, AMF are expected to reduce soil metal bioavailability since metals are sequestered in extraradical hyphae, therefore resulting in lower metal uptake in AM than non-AM plants. A range of environmental factors including soil metal concentrations and their bioavailability, soil absorption/desorption characteristics, as well as endogenous factors (e.g., the fungal properties and inherent heavy metal uptake capacity of plants) may influence the uptake of metals by mycorrhizal plants.

The tyre walls are not filled in the earthship manner, I did not state that. They are filled loosely with soil good enough to grow things in,
whether you plant food or ornamental that is not the issue.
As for beauty, that is in the eye of the beholder, and I will disagree with your opinion.
i work from the aspect of reuse, low cost and tyres meet that criteria.
As for outgassing, leaching etc I am still waiting for facts, not guesses or assumptions.

John, the earthship comments weren't for your benefit, but rather for those talking about using them buried in whatever manner.

And I don't call statistically significantly higher cancer rates among people who work with tires guesses or assumptions.

The data about leaching and off-gassing apply to whole tires as much as the higher surface-area chips. The whole tires will just pollute less for a lot longer.

I am not saying you can't do what you're doing. I am saying that I don't think tires are safe for use in conjunction with living spaces or food production on any terms.

The OP asked if they are dangerous for health and/or nature. Based on what a number of posters have said about toxic effects on soil life, the effects of tires used as coral reefs, and cancer rates in the industry, I can't see how the answer could possibly be no.

I am certainly not going to go to all the trouble of encouraging a resilient food system to grow all my food for me and mine, only to find out later that it's been slowly killing us. It would be cheaper and easier to just go to the supermarket.

-CK

Thanks for the explanation.
I don't use the tyre walls for food, just flowers, greenery,  insect attracting plants, low stuff.
I live in a hot dry climate, so anything with a bit of soil can add a bit of brightness to the place.
I am with you on using them in a house that is well sealed, I have no proof they don't cause harm, but I can smell them when I carry them around and just don't think its a good idea
to live in something that smells.

I have used them as low walls to stop that freezing breeze that can come in around a fire, I have built low fence and gateway entrances on properties with them.
I see their beauty in the use of an object that is usually a problem to get rid of.
But I can say I have read of experiments in turning them into fuel for cars etc .
I just cannot recall the full story, but if that happens, we may not be able to get them anyway.
regards

John C Daley wrote: But I can say I have read of experiments in turning them into fuel for cars etc .
I just cannot recall the full story, but if that happens, we may not be able to get them anyway.

In one of my former post  I wrote: the products form scrap tire pyrolysis are:Oil, gas, coke.
"The oil obtained has a similar composition to heavy fractions from crude oil distillation thus after refination can be used as a fuel.
The gas is used as pirolisis energy source. The coke was considered  a waste. although there were trials to find an application for it.
unfortunately the process is not economically viable unless  the price of a oil barrel reaches 197$

As open air storage has been prohibited by law in EU it's cheaper to send  scrap tires for landfilling in Kuwait.
where sooner or later they will burst in flame due to self ignition and will contaminate our Mother Earth
(almost like wet hay. And almost  the same strain of bacteria is responsible for it )

Chris Kott mentioned an environmentally viable disposal for tyres (we Brits spell it correctly, though it may tire you North Americans to hear that!) 

A company in Wales has been running a pilot plant that will recycle the materials on a small as well as a large scale.  If it has no problems in real life, it could be the answer:
https://www.letsrecycle.com/news/latest-news/tyre-recycling-technology-successfully-tested-in-wales/

David Croucher wrote:Chris Kott mentioned an environmentally viable disposal for tyres (we Brits spell it correctly, though it may tire you North Americans to hear that!) 

A company in Wales has been running a pilot plant that will recycle the materials on a small as well as a large scale.  If it has no problems in real life, it could be the answer:
https://www.letsrecycle.com/news/latest-news/tyre-recycling-technology-successfully-tested-in-wales/

WOW! Thanks for the link ... I graduated in 2002...but still try to know what's going on in the topic of scrap tire utilisation. The art is from 2006
do you happen to know how the plant is  doing nowadays ?
I'm going to google for it anyway.
A piece of good info  
You made my day.

Jura Rafal wrote:For me the most scary way of scrap tires utilisation was creating a .....reef of them.
introducing  such a contaminant into such extremely fragile habitat made my soul scream.

It seems my gut feeling was right as to toxicity of scrap tyre leachate in sea waters enviromnment.

Florida's 'Tire Reef' Has Turned Into an Environmental Disaster

Wow, thank you everyone that helped giving a little brick of information and, also, ideas and personal observations on this issue.
For me, I'm only convinced once more that:

1. The way we make tires today is dangerous for both health and nature, and a new design of the product/system is emergent.
2. There are relatively safe ways of reusing tires, once you avoid close contact and the fragmentation of it, which usually occurs faster when in exposure to the sun, or air, or liquid water. Also, using tire crumbs is probably not a good idea since it has been associated with diseases and soil leaching (think an infographic concerning safe uses for tire would be great).

Also, you convinced me there are some options of turning tires into useful things such as carbon and fuel, and that these might show a path towards a better tire-scenario.
I'm pretty happy with all the things brought here,
Thanks once again,
G.L

  Dear all,
Sorry for my english (i’m Italian). I’ve found this discussion really interesting. My doubt is that the discussion missed a fundamental point “TIME”. Most of the chemical you mention are present in all the building materials. Zinc and chromium are present in all metallic fence, organic component are in all colorant and paint. The main point is the amount of release and time. Consider using tyre probability destroy it millimeter each year and these materials go into the ground by rain water. My opinion is how inert is tyre and how many years need to release chemicals? Of course if you compare with natural wood, no game, but compared with painted wood or painted metal or other plastic probably is safer. I would try to see if there is some scientific paper on release profile over the time. The only proof o have is close to my house there are 2 large mass of garbage , one are tyre and the other are metal and plastic. The soil arround the tire are full of vegetables  ariund the other the soil is dead. Of course is not science because I don’t know what the cumulus of garbage contain..
If I found some info i’ll Write here. Please do the same so we can create a good repository for many people that are using this solution in the Garden
Ciao
Marco

I researched using tires to do an earth berm some what in ground green house.  My thinking was using big scraper tires.   Big solid wall fast was the thinking.  What I learned looking looking at the research on tires was that small quantities of tires don't seem to be a problem for growing stuff.  Most of what comes off the tires is VOCs and zinc.  The zinc in trace levels is actually good for the plants.  And the VOC's some plants actually metabolize along with other life forms.  And in a green house that is heavily ventilated anyway they should be safe.  I gave up on the idea though because public opinion has tires as totally toxic.  So therefore any produce from such a green house would be toxic was the public feeling in nearly everyone I talked to.  In this case perception is truth no matter what the science says.  I did find one funny thing in all of this.  One of the guys I talked to was totally against tires in a greenhouse but turned right around and wanted to build a tire wall earthship home.

Yes. And zinc in higher levels than trace amounts is toxic.

In the human diet, too much zinc can displace iron and copper.

High levels of zinc in the soil can be tolerated by some plants that have close symbiotic relationships with certain mycorrhizal fungi, but generally speaking, high levels of zinc will be sequestered in the same manner as other heavy metals.

As to the VOCs, if they can cause cancer in humans working in the industry, I don't think I would choose to grow my food in soil contaminated with them. I don't think I would want to harm my soil that way at all. I don't see the sense in forcing the soil biology into repair and sequester mode when I would rather it help grow my food for me.

Plus, how do all those contaminants affect communication between plants, fungi, and other living things in the soil? Is the soil life likely to contract diseases analogous to the ones tire exposure can lead to in humans? We are already finding nutritional deficiencies in plants grown in sterilised dirt that might be contributing to the Western obesity phenomenon. What would cancerous or diseased soil life do to the food grown in it?

I don't understand why anyone would risk it. Why contaminate your soil and food any more than necessary?

I don't see the advantage. Ram some earth between forms. Fill some earthbags. Use wood. Just keep the tires away from your food web. There's considerable cognitive dissonance involved in trying to grow nutritious food in thriving soil, but containing said systems with toxic elements. It's a lot of work to go to just to poison yourself.

-CK

Gabriel Lavinsky wrote:Hi people, first sorry for my English (I'm from Brasil). The deal is, having read some stuff about toxicity of tires, and that it should not be used for producing edible vegetables because of it's leaching effect on the soil and water; or even studies concerning dangerous uses of rubber crumb on soccer fields and playgrounds (check this for more info: http://www.plasticfieldsfornever.org/turf_report07.pdf).
Considering all this info, i would really like to understand if some uses of reused tire are really interesting, such as using it for leveling the ground, burying it for ecological sanitary uses or for building house walls with it. Any info you know about it, and if is there a conclusion on whether there is a safe use for reused tires, will be very welcome!

I agree your english is quite good, actually. There is a place near our neighborhood where they are building a community structure, it has used tiers filled with concerete holding up lights for the road inside.. a bit creative I thought.