In conjunction with climate week, the Massachusetts Bay Transportation Authority plans to issue $574-million worth of mostly sustainable bonds on Sept. 26, the agency announced in a statement. This is believed to be the first time a tax-exempt Sustainability Bond will be sold in the U.S. “Establishing clear environmental and social priorities will help us prioritize engineering and construction projects and determine which might be most beneficial to our constituents,” said MBTA Treasurer Paul Brandley. Our commitment to sustainability extends to the engineering and construction processes themselves. The more thoughtful we are in how we procure materials, dispose of waste, et cetera, will lead to better project outcomes.” The international nonprofit Climate Bonds Initiative estimates $118 billion of Green Bonds were issued in 2016.