In 2022, we partnered with Prometheus Materials to bring a carbon-absorbing, algae-based cement replacement to create carbon-negative buildings. Late last summer, we began testing this material as exterior paving at The New York Climate Exchange—an international center to develop solutions to the climate crisis with Stony Brook University—on Governors Island in New York. The project began with 10 cubic yards of roadway and will continue across other parts of the campus in 2026.

The cement mix, the ProZERO™ supplemental blend, replaces 40 percent of traditional cement to significantly reduce embodied carbon. Providing the strength of traditional, high carbon concrete, the blend uses two mechanisms to sequester and remove CO2: photosynthesis during the algae’s growth and carbonate mineralization, a chemical reaction between carbon dioxide and metal to create a solid mineral.

“The Exchange is envisioned as a living laboratory—one where sustainability is embedded in every design and material choice,” said SOM Venture Architect Chas Peppers. “Incorporating ProZERO™ carbon negative cement and concrete into their climate campus and our other SOM projects demonstrates the power of innovation when design, engineering, and material science come together to confront the climate crisis head-on.”