United States                Air and Radiation           EPA420-F-03-034
 Environmental Protection                               September 2003
 Agency

 Office of Transportation and Air Quality

                    of         and
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77?e (7. S. Environmental Protection Agency (EPA) is issuing a direct final
rule with a corresponding proposed rule that will ensure more consistent
use of the same methodology across EPA motor fuel regulations and
allow for improvements in the test method procedure that will ensure
better operation.  Specifically, we are updating an American Society of
Testing Materials (ASTM) designated test method, ASTM D 1319, to the
most recent 2002a version which, when adopted, will supercede earlier
versions of this method in EPA's motor vehicle fuel regulations.
Background
Manufacturers of gasoline and diesel motor vehicle fuel are required to
measure certain fuel properties in order to demonstrate compliance with
our motor vehicle fuels programs. ASTM test method D 1319 is cur-
rently a designated test method for measuring olefms in gasoline and
aromatics in diesel motor vehicle fuel; it is also an alternative test
method for measuring aromatics in gasoline. Aromatics and olefms are
very important fuel parameters to measure in both gasoline and diesel
motor vehicle fuel because they may lead to the formation of air toxic
compounds in motor vehicle exhaust emissions. Because EPA issued
rules related to test methods at different points in time, the regulations
currently cite three different versions of D 1319 (published in three
different years) for each of the applications mentioned above.
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Overview of Rule
Updating ASTM D 1319 to the 2002a version in our regulations for each
of these three applications will ensure more consistent use of the same
methodology across EPA motor fuel regulations as well as allow for
improvements in the test method procedures that will ensure better
operation. The clean air benefits of EPA's gasoline and diesel motor
vehicle fuel programs will continue to be realized. There will be no
adverse health or environmental impact as a result of this test method
update.

These test method changes will be effective sixty days after publication
of the final rule in  the Federal Register. We are confident that sixty days
is sufficient lead time for industry to become familiar and implement this
updated ASTM test method. The proposal also solicits comments on this
change. However,  we do not anticipate any adverse comments and
believe the industry will be very supportive of this change in the regula-
tions.
For Further Information
You can access the proposed rule on the Office of Transportation and Air
Quality Web site at:

       www.epa.gov/otaq/rfg_regs.htm#testing

For further information about the proposed rule, contact Joe Sopata at:

       U.S. Environmental Protection Agency
       Office of Transportation and Air Quality (6406J)
       1200 Pennsylvania Avenue NW
       Washington, DC 20460
       (202) 564-9034

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