Baltimore, one of the first U.S. cities to mandate LEED, has switched to the International Green Construction Code 2012 as an overlay to the city's building, fire, and related codes. According to Green Building Law Update, published by Stuart Kaplow, an environmental attorney:

Council Bill 14-0413 repeals that existing law and commencing April 1, 2015 expands its scope and breadth with a new Baltimore Green Construction Code to apply to all new construction and “all repairs, additions, or alterations to a structure and all changes of occupancy” with very few exceptions (.. one or two family dwellings, etc.).

Significantly, the new Green Code does not apply to: structures that achieve a LEED Silver rating; residential and mixed use buildings of five stories or more that comply with the ICC 700 at the Silver performance level for energy and Bronze level for other categories; and, to structures that comply with ASHRAE standard 189.1. The new enactment allows the Code official to accept third party certification of compliance with these alternative compliance paths ... the new Green Code alters the form IgCC with 32 pages of edits, including that it requires “at least 50% of the total building materials used” in a building of 25,000 square feet or greater, must be recycled, recyclable, bio-based or indigenous (within 500 miles), where the form code threshold is not less than 55% of buildings of all sizes.

Read More and check out the following videos to learn more about the International Green Construction Code.