Carbon Cell is an expanded foam that reduces the need for conventional, fossil fuel-based foams while enabling significant carbon sequestration. Using biochar, a carbon-negative material sourced from biomass that would otherwise be burned or decomposed, we have created a high-performance, non-toxic, expandable, fully biodegradable foam. Carbon Cell has a renewable supply chain composed of organic waste and, because it is biodegradable and non-toxic, it can be reintegrated into the biosphere at end of life. Carbon Cell leverages the inherent properties of biochar – non-toxic, highly porous, lightweight, large surface area – to achieve low thermal conductivity and much better compressive strength than EPS. The top uses of EPS are thermal insulation and packaging - places where Carbon Cell can provide a carbon-negative, biodegradable, and non-toxic alternative.