The common plastic foam block is generally constructed out of ethylene-vinyl acetate, or EVA, a petroleum-derived plastic. It’s difficult to recycle and persists in our ecosystem for centuries before eventually degrading and leaving behind toxic microplastics. We think that goes against the core ethos of yoga.

Wooden yoga blocks are often created from virgin wood sources, meaning standing trees are cut down for the purpose. Although it’s possible for the wood to come from reclaimed sources or certified responsibly managed forests, that’s not always the case – and any time a tree is felled, it harms the local ecology.

Because they are heavy, wood blocks also have a high carbon footprint from shipping. When they have a varnish coating, it’s made from petrochemicals. Wooden blocks are comparatively pricey, heavy and can be too hard for some weight-bearing positions.

Although bamboo blocks are made from a fast-growing renewable material, they are generally made of laminated bamboo sheets that are steam-pressed into shape and held together with strong synthetic (petrochemical) glues. In addition, their manufacturing process is energy intensive and they are heavier than paperboard blocks, which increases their carbon footprint when shipping.

The blocks you’ve likely seen are made of what’s called agglomerated cork. They are produced by grinding off-cuts of cork bark into granules, and then gluing them together to form blocks. This glue is synthetic – often polyurethane plastic derived from fossil fuels – meaning the block is not biodegradable, and can only be “downcycled” into lesser grades of agglomerated cork products.

We have yet to find a brand of cork blocks made without plastic binders – even brands claiming they are “nontoxic” still use plastic, according to laboratory tests we’ve conducted. The benefit of cork is it’s a renewable material and has a great texture. In the future, we hope to produce a plastic-free cork block made entirely with renewable, bio-based binders.

They are! We use strong, plant starch-based adhesives. They are bio-based, which means they come from natural sources – not fossil fuels.