The proposed bill introduces the "Buildings Carbon Emissions Reduction Act" as a new chapter in Title 42 of the General Laws, aimed at regulating large developments in terms of their carbon emissions. It defines "large developments" as those constructed on parcels exceeding 50,000 square feet and requiring a carbon impact report to assess whether they can meet their energy needs with 100% clean energy by the year 2050.

The bill stipulates that no permits for such developments can be issued if the initial application is submitted after December 31, 2026, unless certain conditions are met. These conditions include a finding by the permitting body that achieving an all-electric design is physically or technically unfeasible, with specific criteria for substantiating such claims. Modifications to the all-electric requirement may be granted, but the installation of natural gas or oil systems is strictly limited to what is necessary for compliance, and the modified design must provide equivalent health, safety, and fire protection to an all-electric design.

Additionally, the bill provides exemptions for developments primarily used as hospitals, medical facilities, laboratories for biological research, or restaurants. The act is set to take effect upon passage, emphasizing the state's commitment to reducing carbon emissions in building practices.