California’s Governor Brown signed into law the California Buy Clean Act, AB 262, on October 15, 2017. The manufacture and processing of many construction materials is a significant source of greenhouse gas (GHG) emissions. The progressive new California mandate requires state authorities to only award state infrastructure contracts to construction contractors using low-carbon emitting versions of designated materials. Cement, the largest contributor of construction materials GHG emissions, is noticeably absent from the new law. Hopefully, as the California Buy Clean Act is implemented and the GHG limitations for construction materials become customary, there will be greater openness to also setting emission limits for cement.