&EPA
                  United States
                  Environmental Protection
                  Agency
                     Air and Radiation
                                        EPA420-F-99-011
                                        May 1999
                  Office of Mobile Sources
Regulatory
Announcement
                  Diesel Fuel Quality: Advance Notice of
                  Proposed Rulemaking
                  The U.S. Environmental Protection Agency (EPA) is considering setting
                  new quality requirements for diesel fuel to enable the use of a new
                  generation of emission control technologies for diesel engines. These
                  changes would provide large reductions in the emissions of pollutants
                  that contribute to the harmful effects of ozone and particulate matter.
                  The Advance Notice of Proposed Rulemaking (ANPRM) summarizes
                  key issues surrounding diesel fuel changes and seeks input from
                  interested parties.
                  Background
                  Diesel engines used to power
                  trucks, buses, some automobiles,
                  and nonroad equipment (such as
                  farm tractors and bulldozers) are
                  major contributors to our nation's
                  air quality problems. Although
                  progress has been made over the
                  last decade in reducing emissions
                  from diesels, they continue to be
                  a large source of oxides of nitro-
                  gen (NOx) and diesel particulate matter (PM). NOx contributes to
                  ground-level ozone, the main ingredient in smog. Diesel PM causes
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adverse respiratory health effects, and is also thought to pose a potential
cancer risk. In addition to the impacts of emissions from heavy-duty and
nonroad diesel engines, automobile manufacturers are planning to expand
the use of diesels in sport utility vehicles and other fast-selling light-duty
vehicles over the next few years. This may greatly add to the diesel's
impact on the environment.
Highlights of ANPRM
To reduce the environmental impact of diesel emissions, EPA is consider-
ing requiring improvements in the quality of diesel fuel. New diesel
emission control technologies are being developed with the potential to
reduce NOx emissions by 50 to 75 percent, and PM emissions by over 80
percent. However, some of these technologies appear to be very sensitive
to sulfur in the fuel. Currently, highway diesel fuel sulfur is regulated to a
maximum of 500 parts per million (ppm) and nonroad diesel fuel is not
regulated by EPA at all. Diesel engine manufacturers have projected that
sulfur levels must be reduced to 30 ppm,  or perhaps even lower, to enable
these sulfur-sensitive technologies to work.

This advance notice is tied closely to EPAs recent proposal for Tier 2
emission standards for passenger cars and light trucks, including sport
utility vehicles, pickup trucks, and minivans. Under these standards,
diesel vehicles would have to meet the same standards as gasoline ve-
hicles. As part of the
Tier 2 program, EPA   fl
also proposed to
lower sulfur levels in
gasoline, in part
because it will enable
advanced catalyst
technologies needed
to achieve the new
standards. With this
ANPRM, the Agency
is seeking comment on the merits of improving the quality of diesel fuel
as well, as an enabler of advanced technologies for diesel emission
control, without which diesel vehicles may not be able to meet Tier 2
standards. These technologies, if proven viable, would likely transfer to
heavy-duty highway applications, and eventually to nonroad applications,
yielding large NOx and PM benefits.

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Issues Related to Diesel Fuel Quality Control
The advance notice seeks comment on many issues related to diesel fuel
quality control, including:

   Should fuel parameter changes other than sulfur reduction be pur-
   sued?
•  How effective will advanced sulfur-sensitive emission control tech-
   nologies be?
•  What sulfur levels are needed and when?
•  What would the refinery and distribution costs be?
•  How soon can low sulfur fuel be made available?
•  What would be the impact on small refiners?
•  How can the program be made flexible for refiners and still be effec-
   tive?
•  Would a phased approach be appropriate, such as an early introduc-
   tion of low sulfur fuel for light-duty vehicles affected by the Tier 2
   program?
   Should nonroad fuel be  desulfurized to current highway fuel quality
   levels?
Public Participation Opportunities
We welcome public comments on this advance notice from all interested
parties. You may submit written comments to EPA up to 45 days after the
ANPRM is published in the Federal Register. For instructions on submit-
ting written comments, please see the Federal Register notice. It is
available from the EPA Air Docket by calling (202) 260-7548; please
refer to Docket No. A-99-06.

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The address for submitting written comments is:

    Docket No. A-99-06
    U.S. Environmental Protection Agency
    Air Docket (6102)
    Room M-15 00
    401 M Street SW
    Washington, DC 20460

The advance notice is available electronically via the EPA Internet site at:

    www.epa.gov/oms/fuels.htm

Decisions on diesel fuel quality need to be made quickly so that the Tier
2 program may be implemented in the most coordinated and cost-effec-
tive manner. We therefore plan to pursue this action on an accelerated
schedule. If, following this advance notice, we decide that a proposal is
warranted, we plan to publish a notice of proposed rulemaking later this
year, and a final rule as soon as possible after that. The proposal stage
would include a public hearing and additional opportunities to submit
written comments.
For More Information
Additional documents related to the advance notice are available elec-
tronically at the Internet site listed above, or by contacting:

    Carol Connell
    U.S. Environmental Protection Agency
    Office of Mobile Sources
    2000 Traverwood Dr.
    Ann Arbor, MI 48105
    E-mail: connell.carol@epa.gov

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