I had just about forgotten the typical volatile organic compound (VOC) smell of a new running shoe, until Bob left a pair in our closet last night. (Why, you wonder, is Bob not wearing our new La Vida’s? Because, unfortunately, his feet are still too big for our largest La Vida size 12.)
You might think that because I work in a shoe factory I smell VOC smells all the time. But I don’t–because we don’t put any chemicals that emit VOC’s into our shoes.
Bob’s running shoes reminded me of what exactly gives rise to that smell…a complex mixture of VOC’s from chemicals such as benzenes, toluenes, and formaldehydes. The smell also brought back the angst–and headache (just think about that acronym…”volatile” and “compounds”…???)–I had when I visited shoe factories in China and learned how a typical running shoe is made.
For the last 30-40 years, running shoes have been made, largely in China, with a cushioning midsole comprised of a type of ethylene foam, softened with a vinyl chemical, called EVA (ethylene vinyl acetate). Additional chemicals are used not only to treat the foam but especially to adhere the foam with other parts of the shoe.
The adhering of the various parts of the shoe together is probably the most toxic of all athletic shoe-manufacturing processes. The adhesives and primers typically include those benzenes, toluenes, formaldehydes and other chemicals that emit high levels of VOCs. Not only is this an especially toxic manufacturing process, typical athletic shoes continue to off-gas while you own the shoes, run in them, and keep them in your home.
Why the toxicity in the first place?
It’s a function of the manufacturing “arms race” to cushion impact–an arbitrary assumption–that cushioning impact protects the joints from long-term injury. My research informs that a shoe sole shouldn’t be designed to absorb impact but rather it should be designed to respond in tune with when joint torques and all other forces through the body are at their peak. This design criteria of OESH effectively rules out the use of EVA foam and all other types of gels and plastic “shock absorbers” currently used in running shoes. It required developing a uniquely responsive material positioned under the foot in such a way that it does not “absorb impact” but rather responds appropriately at the right time – when joint pressures and all other forces through the body are at their peak.
Such a design and the manufacturing of the correct type of responsive sole, demands an entirely unique shoe manufacturing process. And the OESH process, which we’ve brought to a new manufacturing scale in the La Vida, is sustainable and green. Only the fabric stitched to make the upper comes from Asia. As every raw material we use in manufacturing and attaching the La Vida sole is both known and tested independently, we know that no VOC chemicals or compounds exist in the La Vida. The smell of Bob’s running shoes reminded me of how incredibly unique La Vida is within the athletic shoe industry.
The focal point of OESH is creating biomechanically-appropriate footwear. But without our proprietary–and green–methodology, we believe it is impossible to integrate the extraordinary “level playing field” of the OESH interior atop the responsive sole. This we’ve done–AND eliminated the most toxic part of running shoe manufacturing. None of those horrible VOC’s are in La Vidas.