In June 2025, the City of Phoenix, AZ adopted the 2024 International Residential Code (IRC) along with a handful of natural-building appendices including Appendix BL, Hemp Lime (Hempcrete) Construction. But as far as anyone in the hemp building industry can tell, it went largely unreported.

Over the past year, nine hemp-based building material manufacturers got the chance to take part in a program the US hemp industry has needed for a long time: the creation of standardized, third-party test data required by U.S. building codes and permitting agencies.

Almost two decades after a pioneering hempcrete structure was built near the Pine Ridge Reservation in South Dakota, members of the Oglala Sioux Tribe’s Makoce Agriculture Program learned how to spray hempcrete this summer.