Office of Transportation                            EPA420-F-06-021
United States         and Air Quality                                  February 2006
Environmental Protection  	
                Control of Hazardous Air
                Pollutants from  Mobile Sources
                The U.S. Environmental Protection Agency (EPA) is issuing a
                proposed rule to reduce hazardous air pollutants from mobile sources.
                Hazardous air pollutants, also known as air toxics, include benzene
                and other hydrocarbons such as 1,3-butadiene, formaldehyde,
                acetaldehyde, acrolein, and naphthalene. Air toxics emitted by motor
                vehicles and other moving sources (called "mobile source air toxics,"
                or MSATs) contribute significantly to the nationwide risk from breathing
                outdoor air toxics. The proposed standards would significantly lower
                emissions of benzene and the other air toxics in three ways:  (1)
                by lowering benzene content in gasoline; (2) by reducing exhaust
                emissions from passenger vehicles operated at cold temperatures
                (under 75 degrees F); and (3) by reducing emissions that evaporate
                from, and permeate through, portable gasoline containers (gas cans).
                Section 202(1) of the Clean Air Act requires EPA to set standards to con-
                trol hazardous air pollutants from motor vehicles, motor vehicle fuels,
                or both. EPA published a final rule under this authority in March 2001
                that established toxics emissions performance standards for gasoline
                refiners and committed to additional rulemaking to evaluate the need for
                and feasibility of additional controls. This proposal fulfills that commit-
                ment from the 2001 rule.

                In addition, EPA is proposing emission standards for gas cans under the
                consumer products authority of the Clean Air Act (section 183(e)).

Reason to Reduce Mobile Source Air Toxics
MSATs are known or suspected to cause cancer or other serious health
or environmental effects. Benzene is of particular concern because it is
a known carcinogen and most of the nation's benzene emissions come
from mobile sources.  People who live or work near major roads, or
spend a large amount of time in vehicles, are likely to have higher expo-
sures and higher risks.  People living in homes with attached garages are
also likely to be exposed to benzene levels that are higher than average.

Many MSATs are part of a larger category of mobile source emissions
known as volatile organic compounds (VOC), which contribute to the
formation of ozone and possibly particulate matter (PM). Ozone and PM
can contribute to  serious public health problems, including premature
mortality, aggravation of respiratory and cardiovascular diseases, damage
to lung tissues and structures, altered respiratory defense mechanisms,
and chronic bronchitis.
Fuel Program
EPA is proposing that, beginning in 2011, refiners would meet an annual
average gasoline benzene content standard of 0.62 percent by volume
on all their gasoline, both reformulated and conventional, nationwide.
The national benzene content of gasoline today is about 0.97 percent.
(Gasoline sold in California would not be covered because California has
already implemented more stringent standards similar to those EPA is

EPA is proposing a nationwide averaging, banking, and trading program
as part of the average standard. The Agency is expecting gasoline in all
areas of the country would have lower benzene levels than they do now,
and there would be less geographic variability in gasoline benzene levels.
EPA is proposing special compliance flexibility for approved small refin-
ers or any refiner facing extreme unforeseen circumstances.
Vehicle Program
EPA is proposing new standards to reduce non-methane hydrocarbon
(NMHC) exhaust emissions from new gasoline-fueled passenger ve-
hicles. NMHCs include many mobile source air toxics, such as benzene.
Recent research indicates that the current test procedures often do not
result in robust control of NMHCs at colder temperatures below 75 de-
grees. Therefore, we are proposing a cold temperature test where passen-

ger vehicles would be subject to an NMHC exhaust emissions standard.
As shown in Table 1, each manufacturer's vehicles would be subject to
a sales-weighted fleet average NMHC level of 0.3 grams/mile for lighter
vehicles weighing 6,000 pounds (Ibs) or less. Vehicles above 6,000
Ibs (which include trucks up to 8,500 Ibs and passenger vehicles up to
10,000 Ibs) would be subject to a sales-weighted fleet average NMHC
level of 0.5 grams/mile.  The standard would phase in between 2010 and
2013 for the lighter vehicles, and between 2012 and 2015 for the heavier
vehicles. A credit program and other provisions would provide flexibil-
ity to manufacturers, especially during the phase-in periods.

 Table 1 - Proposed Cold Temperature NMHC Standard and Phase-In
Vehicle Weight Class
6000 Ibs or less
6001 to 8500 Ibs, plus
passenger vehicles up
to 10,000 Ibs
NMHC Emission
Level (grams/mile)
Phase-In Schedule" (percent)




 A Gross Vehicle Weight Rating
 B Percent of each manufacturer's fleet, by model year, that must comply with the standard.

Along with the vehicle exhaust standards, we are also proposing more
stringent evaporative emission standards for new passenger vehicles.
The proposed standards are equivalent to California's standards and
would codify the approach that manufacturers are already taking for 50-
state evaporative systems. We are proposing to implement the evapora-
tive emission standards in 2009 for lighter vehicles and in 2010 for the
heavier vehicles.
Gas Can  Program
EPA is proposing standards that would limit hydrocarbon emissions
that evaporate from or permeate through gas cans. Gas cans (portable
gasoline containers) are consumer products used to refuel a wide variety
of gasoline-powered equipment, including lawn and garden equipment,
recreational equipment, and passenger vehicles that have run out of
gas.  Starting with containers manufactured in 2009, the standard would
limit evaporation and permeation emissions from these containers to
0.3 grams of hydrocarbons per gallon per day. We are also proposing
test procedures and a certification and compliance program in order to
ensure that gas cans would meet the emission standard over a range of
in-use conditions.

EPA has worked closely with major gas can manufacturers and it is ex-
pected that the new cans will be built with a simple and inexpensive in-
ner coating and other minor modifications to comply with the proposed
Program Benefits
The proposed fuel benzene standard and hydrocarbon standards for
vehicles and gas cans would together reduce total emissions of mobile
source air toxics by 350,000 tons in 2030, including 65,000 tons of
benzene. As a result of this proposal, in 2030, passenger vehicles would
emit 45 percent less benzene, gas cans would emit 78 percent less ben-
zene, and the gasoline would have 37 percent less benzene overall.

In addition, the hydrocarbon reductions from the vehicle and gas can
standards would reduce volatile organic compound (VOC) emissions
(which are precursors to ozone and can be precursors to PM2 5) by over
1 million tons in 2030.  The proposed vehicle standards would reduce
direct PM25 emissions by 20,000 tons in 2030 and may also reduce
secondary formation of PM25. Once the regulation is fully implemented,
these PM reductions will result in 1,000 premature deaths avoided annu-

We estimate that most of the benefits of this proposal would come from
the reduced direct PM25 emissions from the vehicle standards, estimated
to be about $6 billion in 2030.  Some additional benefits would come
from reductions in mobile source air toxics and VOCs, although we have
not been able to monetize these benefits.
Estimated Costs per Program
The additional cost of producing gasoline to comply with the new ben-
zene standard is expected to average $0.0013 per gallon.  This per-gallon
cost would result from an industry-wide investment in capital equipment
of $500 million to reduce gasoline benzene levels, or an average of $5
million in capital investment in each refinery that adds such equipment.

We estimate that the annual net social costs of this proposal would be
about $200 million in 2030 (expressed in 2003 dollars). These net social
costs include the value of fuel savings from the proposed gas can stan-
dards, which would be worth $82 million in 2030.

We estimate that the additional cost to manufacturers would be less than
$1 per vehicle. The costs would be associated with vehicle research and
development and recalibration, as well as facilities upgrades to handle
additional development testing under cold conditions. We are not antici-
pating additional costs for the proposed vehicle evaporative emissions
standard since manufacturers will likely continue to produce 50-state
evaporative systems that meet California's standards.

The average additional cost of producing gas cans that comply with the
new standards would be less than $2 per can.  The reduced evaporation
from gas cans would result in fuel savings over the  life of the can that
would more than offset the increased cost for the gas can.
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. EPA-HQ-OAR-2005-0036. In addition, you
can access the proposed rule and related documents on EPAs Office of
Transportation and Air Quality (OTAQ) Web site at: http://www.epa.
gov/otaq/toxi cs. htm

For More Information
For more information on this proposed rule, please contact Kathryn
Sargeant, Director, Health Effects, Benefits, and Toxics Center, at:

U.S. Environmental Protection Agency
Office of Transportation and Air Quality
2000 Traverwood Drive
Ann Arbor, MI 48105