A reader wrote to me as a comment, asking about a yoga mat. Doing research on the response opened up the whole issue of materials used to make yoga mats. So I turned it into a post.

The issue with yoga mats is that in the past, most were made with polyvinyl chloride (PVC), which is made from and emits vinyl monomer (VCM), phthalates, and lead. Together, these materials release chemical gasses that can cause cancer, endocrine disruption, and all kinds of neurological problems.

So within the yoga world, there had been a movement going on towards finding the perfect “PVC-free” yoga mat.

Polymer Environmental Resin (PER)

The yoga mat that prompted this post is made from a material called “PER.”

Somewhere the reader found the following and pasted it into the comment. I’m not sure where she got this as I couldn’t find it on the page of the link she gave me.

This mat has been Oeko-Tex 100 Tested and Approved and are Safe, Non Toxic, Hypoallergenic, No Phthalates, Phenols or PAHS, Free from Latex, Rubber or Silicone.

4) Our Patented PER Mats are made from a new non toxic resin, free of rubber, silicone, latex and does not emit any toxic chemicals or gases.

Please note that PER is a patented product and not PVC as many less expensive products. Be careful of Imitations not registered PER;

5) The mat has been successfully tested against harmful substances; Oeko-Tex Standards Class-1- Baby Articles and US FDA approved by SGS”

So what is this PER and is it really safe?

PER is the acronym for Polymer Environmental Resin. This is kind of a strange name because usually substances are named for the chemicals used to make them. This name simply says it’s a polymer (plastic) resin that has environmental benefits.

Ironically, PER starts as polyvinyl chloride (PVC), which has been plasticized and stabilized with acetyl tributyl citrate instead of phthalates and lead. So it’s not “PVC-free” as advertised. It actually is PVC, with different plasticizers and stabilizers.

Certainly acetyl tributyl citrate is much less toxic than phthalates and lead, so this is an improvement, but what I’m concerned about is that the basic vinyl chloride monomer (VCM) used to make PVC is itself a carcinogen. Swapping out the plasticizers and stabilizers doesn’t change that.

Their claim that it contains no phthalates, phenols, PAHs, latex, rubber, and silicone is certainly true.

They also say it is nontoxic and does not emit any toxic chemicals or gasses. I’ve never seen this material, but I do know something about PVC. And it just doesn’t react 100%. There tends to be some small amount of unreacted VCM. But it only takes a small amount of VCM to be toxic.

I went to the website of the yoga mat in the link the reeder gave me. I didn’t see any mention of Oeko-Tex or a certificate. Maybe it’s there, but I didn’t find it on a sales page.

I also couldn’t find any data on the health effects of PER, either pro or con. No Safety Data Sheet. Nothing.

Here are the only two references I could find on PER:

APPROPEDIA: Polymer Environmental-Friendly Resin

STACK EXCHANGE CHEMISTRY: What is Polymer Environmental Resin (PER)?

Thermoplastic Elastomers (TPE)

Another material used to make PVC-free yoga mats is TPE.

TPE is the acronym for ThermoPlastic Elastomers, a class of copolymers that have the elastic properties of rubber and re-meltable property of thermoplastics.

There are six generic classes of TPEs:

  • Styrenic block copolymers (TPE-s)—made of styrene
  • Thermoplastic olefins (TPE-o)
  • Elastomeric alloys (TPE-v or TPV)
  • Thermoplastic polyurethanes (TPU)—made of polyurethane
  • Thermoplastic copolyester—made of polyester
  • Thermoplastic polyamides

But Safety Data Sheets say only that the material composites are trade secrets.

TPE is such a nebulous term that it could mean many things.

It’s certainly a petroleum product, so if you are sensitive to petrochemicals it wouldn’t be a wise choice.

TPE is being used more and more as an alternative to PVC in various types of products, including medical devices and food packaging.

Oh. Now here is a MSDS for “TPE 5187”: www.ttmarketinginc.com/tds/MSDS-TPE5187.pdf

It lists these ingredients for “TPE”:

  • EPDM [ethylene propylene diene monomer (M-class) rubber, a type of synthetic rubber]
  • Bromine Flame Retardant
  • Antimony Trioxide [another flame retardant]
  • Polypropylene [a nontoxic plastic]
  • Proprietary Stabilizers [who knows what these are]

OK. That’s as far as I need to search. It’s likely most TPEs contain similar ingredients.

Least Toxic Yoga Mats

While PER and TEC are far better than PVC, they are not good enough for me.

Now we get down to the natural materials used to make yoga mats.

There are a number made from natural latex, but many people are allergic to latex or do not like the natural odor (I am one of them).

So then there are a few yoga mats made from natural fibers.

Yogasana Cotton Yoga Mats
Listen to interview with co-founder and owner Kevin Aylward on Toxic Free Talk Radio

Rawganique Hemp Yoga Mats
Listen to interview with co-founders Klaus Wallner and Thammarath “Touch” Jamikorn on Toxic Free Talk Radio

There may be more, but these are two I know about.

I think it’s great that there are “better” alternatives that are less toxic. But why be less toxic when you can be least toxic?

Personally, I’m always looking for the least toxic materials I can find. PER and TPE are still too toxic for me.

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