Bush signs Clean Air Act amendments adding acid rain cap-and-trade

President George H.W. Bush signed comprehensive amendments to the Clean Air Act on November 15, 1990, adding a market-based cap-and-trade system for sulfur dioxide emissions to combat acid rain, tightening urban smog standards, and requiring the phase-out of ozone-depleting chemicals. The legislation passed the Senate 89-10 and the House 401-25, the last major bipartisan environmental legislation enacted. The acid rain program became a model for market-based pollution control worldwide.