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Regulatory

Announcement

Office of Transportation

and Air Quality

EPA420-F-04-014

August 2004

Notice of Proposed Rulemaking to

Revise MSAT Default Baseline Values

The U.S. Environmental Protection Agency (EPA) is issuing a Notice of

Proposed Rulemaking to revise the Mobile Source Air Toxics (MSAT)

Rule default baseline values. This rulemaking also would correct an

error in the MSAT reformulated gasoline (RFG) default baseline value

published in the original rule.

Background

The final MSAT rule, published March 29, 2001 (as Control of Emissions of Hazardous Air Pollutants From Mobile Sources), requires that

the annual average toxics performance level of gasoline produced or

imported beginning in 2002 must be at least as clean as the average

performance level of the gasoline produced or imported during the

baseline period 1998-2000. The toxics performance level is determined

separately for each refinery and importer, as well as separately for RFG

and conventional gasoline.

The MSAT default baseline applies to the gasoline of those parties who

cannot establish a unique individual MSAT baseline under the MSAT

rules. Such parties may not have existed during the MSAT baseline

period, or did not have sufficient gasoline production or import activity

during that period. The default MSAT baseline is an estimate of the

nationwide annual average toxics performance level of gasoline. At the
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time of the rulemaking, toxics performance data from calendar year 2000

was not yet available. In the final rulemaking, we committed to revise

the default MSAT baseline values once the 2000 data became available.

This rulemaking would fulfill that commitment. We are proposing that

the revised values be effective beginning with the 2005 compliance

period.

This rulemaking would also correct an error in the original rule affecting

the originally published RFG default baseline value. The correct value

would be effective for the 2002-2004 compliance periods.

Health and Environmental Benefits

The final MSAT rule set gasoline toxic emission performance standards

to ensure that refiners and importers maintain their average 1998-2000

gasoline toxic emission performance levels. This proposal to update the

default MSAT baseline values would not change the environmental

analyses discussed in the final MSAT rule.

Effect on Industry

The proposed revised conventional gasoline default baseline value is less

stringent than the current conventional gasoline value. The proposed

revised RFG default baseline value is slightly more stringent than the

current RFG value. This outcome for RFG is not unexpected as the

standards recently changed (in 2000) which increased the toxic performance standard from 16.5 percent reduction to a 21.5 percent reduction.

Nonetheless, EPA expects this rule to have minimal economic consequences.

Public Participation Opportunities

We welcome your comments on this proposed rule. For instructions on

submitting written comments, please see the Federal Register notice,

which is available from the EPA Air Docket by calling 202-566-1742;

please refer to Docket No. OAR-2002-0042. In addition, you can access

the proposed rule and related documents on EPA’s Office of Transportation and Air Quality (OTAQ) Web site at:

www.epa.gov/otaq/toxics.htm

Additionally, if requested within 20 days of publication in the Federal

Register, we will conduct a hearing on this proposed rule.
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For More Information

For further information on this proposed rule, please contact Christine

Brunner at:

U.S. Environmental Protection Agency

National Vehicle and Fuel Emissions Laboratory

2000 Traverwood

Ann Arbor, MI 48105

(734) 214-4287

E-mail: brunner.christine@epa.gov