The production of bricks is a challenge for circularity because it requires large amounts of fossil fuels to heat kilns, as well as large amounts of new materials from the ground. American startup BioMason has developed a method to "grow" bricks organically, using sand and bacteria. This process requires water instead of heating, which can be reused, and can source a large amount of its resources from industrial waste. Furthermore, the production process emits no CO2.

Worldwide, around eight percent of global carbon emissions are generated from brick manufacturing. This is primarily because bricks need to be blasted at high temperatures for several days. This process requires high amounts of energy that is hard to recover. For cities with a high need for building materials like bricks, alternative solutions can be a good way of reducing their carbon footprint as well as improving their air quality, which also suffers from traditional brick manufacturing.

The bricks constructed by BioMason do not require any blasting. Instead, they use sand injected with micro-organisms to induce a natural growth process that resembles the process involved in the formation of corals. The main resources needed to feed the bacteria and provide materials for the bricks are sand and water. Because the water can be reused, the process also becomes notably more circular and less energy is lost in production.