The #1 material in yoga mats is polyvinyl chloride (PVC). A 2023 peer-reviewed study published in Materials journal found that PVC is correlated severe health problems including cancer, immune system damage, and hormone disruption (Kudzin, et al). I spent a year practicing daily on a PVC mat before I knew what PVC was. At the time, I didn't know about the materials in yoga mats. I just knew that I was sweating too much in hot yoga class and needed something more stable. Here is what PVC looks like.
The search for stability led me to make the Foundation mat. This search led me out of frustrating relationships, workplaces, and bars, and into more positive, healthy, and long term environments. I showed up to yoga class each day, enjoying a place that accepted me for who I was, while still challenging me to improve every single day. 6 months in, I realized how every small movement I was doing (like chaturanga), which in turn sets up for crow (Bakasana). I did improv comedy multiple times a week, which taught me to laugh when I fell over in Half Moon (Ardha Chandrasana).
Although it feels good to laugh, I was tired of slipping on my yoga mat. I sourced mats made of different materials and finally chose cork. Cork is a phenomenal material. It grows naturally on trees in Portugal and Spain. Portuguese cork growers do not cut trees down to harvest cork, they shave off bark in a 9 year growing process.
Additionally, since cork comes from nature, it is biodegradable. What a beautiful difference cork is from PVC, which is non-biodegradable. Incineration or landfill of PVC releases dioxins, known carcinogens. PVC requires more toxic additives than any other plastic and its synthetic alternatives are not much better.
I looked for other alternatives for the bottom of Corda's Foundation mat. TPE (thermoplastic elastomers) was the next idea. Other yoga businesses were using TPE, which is an improvement over PVC, because it does not require the same toxic plasticizers (lead, cadmium) that PVC does. However, TPE is still made out of petroleum. The customer who switched from PVC to TPE thinking they made an environmentally conscious choice is still buying a petroleum product. TPE ingredients are secret. TPE is a general term. Manufacturers are not required to disclose their formulations, making independent safety verification impossible. Known components of TPE are carcinogenic. The most common and least expensive TPE, Styrene Butadiene Styrene, or SBS, is literally named after its two primary components: styrene and butadiene. The IARC upgraded butadiene to a Group 1 confirmed human carcinogen in 2008, the same classification as tobacco smoke. The EPA classified it as a known human carcinogen in 2002. It is linked specifically to leukemia in exposed workers. And it is structurally unstable under heat, UV, and moisture, the exact conditions of a yoga class.
Annoying. It seemed like every material I tested was flawed and did not seem right for the human body. I resolved to use natural materials for Corda's products. Our Foundation yoga mat uses natural Portuguese cork and natural rubber (which also grows on trees) as the primary backing material. The Corda standard, specifically, is to not include petroleum-derived synthetic polymers, synthetic organic dyes or pigments, to screen the vulcanization system against documented skin sensitizers.
Finally, I felt like the materials of my mat aligned with the values of yoga. I hope that wherever you are, sharing this story helps enforce the truth that we are not permanently subjected to the designs of others. We do have agency to use better materials in our life. I hope you take a big step today and improve the materials in your yoga mat. Thank you.
Gage