x>EPA
    mieJ Sine--,         Office of Transportation                           EPA420-F-04-034
       menwl P,ot«clton   and Ajr Qua|jty                                May 2004
                  Resource
                  Information
                   EPA Diesel Milestones  Since the
                   Clean Air Act Amendments of 1990
                  1993  Highway Low Sulfur Diesel Rule: For the first time, the
                        Agency limits sulfur content of highway diesel fuel to 500 parts
                        per million (ppm).

                  1994  Urban Bus Program: New standards and retrofit requirements
                        for urban buses.

                  1997  Locomotive Rule: Emission standards for nitrogen oxides
                        (NOx), hydrocarbons, carbon monoxide, particulate matter, and
                        smoke for new and re-manufactured diesel-powered locomotive
                        engines.

                  1998  Tier 2 and 3 Nonroad Diesel Rule: Emissions standards for
                        new diesel  engines used in nonroad construction, agricultural,
                        airport and industrial equipment, as well as in certain marine
                        applications. Very few of these engine categories had emission
                        standards in place before the mid-1990s.

                  2004  Highway Diesel Standards: Emission standards to reduce NOx
                        and hydrocarbons from heavy-duty diesel trucks and buses to be
                        implemented in 2004.

                  1999  Commercial Marine Diesel Rule: Final rule to reduce nitrogen
                        oxides and particulate matter emissions from new large marine
                        diesel engines. These engines are used in a variety of capacities,
                        including fishing boats, tug and tow boats, coastal and Great
                        Lakes cargo vessels.

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 2000  2007 Clean Diesel Truck/Bus and Low Sulfur Diesel Rule:
       Comprehensive national control program that will regulate
       heavy-duty diesel trucks and buses and highway diesel fuel as a
       single system. These new standards will apply to model year
       2007 engines and vehicles. Also, reduces sulfur in highway
       diesel fuel by 97 percent (15 ppm) by mid-2006.

       Voluntary Diesel Retrofit Program: Reduce pollution resulting
       from existing diesel vehicles and equipment by encouraging fleet
       owners to install pollution-reducing devices on vehicles and to
       use cleaner-burning diesel fuel.

2002   Recreational Marine: Applied similar standards from 1999
       commercial marine diesel rule to recreational marine diesel
2003   Ocean-Going Vessels: Emissions standards for new marine
       diesel engines on U.S. flagged ocean-going vessels.

       Clean Air Nonroad Diesel Proposal: Proposal to further reduce
       emissions from nonroad diesel engines used in construction,
       mining, industrial, airport and agricultural equipment.

       Clean School Bus USA Program: Reduces children's exposure
       to diesel exhaust by eliminating unnecessary school bus idling,
       installing effective emission control systems on newer buses, and
       replacing the oldest buses in the fleet with newer ones.

2004   Clean Air Nonroad Diesel Rule: The most recent nonroad
       standards will dramatically reduce emissions by  over 90 percent
       from nonroad diesel equipment and dramatically reduce sulfur
       levels by 99 percent from current levels in nonroad diesel fuel
       starting in 2007. This step will apply to most nonroad diesel fuel
       in 2010 and to fuel used in locomotives and marine vessels in
       2012.

       Locomotive and Marine Diesel Engine Standards: EPA is
       issuing an Advance Notice of Proposed Rule and is inviting
       comment on a plan to propose more stringent emission standards
       and other provisions for new and existing locomotives, and new
       marine diesel engines.

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