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Frequently

Asked Questions

 Printed on Recycled Paper

United States

Environmental Protection

Agency

Air and Radiation EPA420-F-02-008

July 2002

Office of Transportation and Air Quality

Effect of Proposed Evaporative

Emission Standards for Marine

Manufacturers

The U.S. Environmental Protection Agency (EPA) is proposing new

evaporative emission standards for gasoline-fueled boats and personal

watercraft. These proposed standards would require most new boats

produced in 2008 or later to be equipped with low-emission fuel tanks

or other evaporative emission controls. This fact sheet describes the

proposed program and its expected impact on boat manufacturers and

fuel tank manufacturers.

Why is EPA regulating marine fuel systems?

We analyzed evaporative emissions from gasoline fuel tanks used in

boats and determined that they emit over 100,000 tons of gasoline

vapors each year across the United States. Most of these emissions occur

either from permeation of the fuel through plastic fuel tanks and rubber

hoses, or as a result of heating of the fuel from normal daily temperature

changes (diurnal emissions). These vapors contribute to the formation of

smog and contain toxic compounds such as benzene. The Clean Air Act

requires EPA to set emission standards to address these problems. These

impacts are described in more detail in “FAQ: Environmental Impacts of

Recreational Vehicles and Other Nonroad Engines” (EPA420-F-01-030,

September 2001).
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Who is responsible for compliance?

The proposed regulations would apply to new boats when they are sold. So it would be

the responsibility of the boat manufacturer to ensure that each boat sold is in compliance

with the new standards. Boat manufacturers could choose to certify fuel tanks and hoses

themselves or to purchase certified fuel tanks and hoses. Fuel tank and hose manufacturers who only sell products to boat manufacturers that certify their boats themselves would

not be required to certify their tanks or hoses separately, but could chose to do so.

What are the proposed standards?

We are proposing standards for diurnal, fuel tank permeation, and hose permeation

emissions. The proposed evaporative emission standards are 1.1 g/gallon/day for diurnal,

0.08 g/gallon/day for fuel tank permeation, and 5 g/m2

/day for hose permeation. This

represents about an 80 percent reduction from the average evaporative emission rate of

current marine vessels.

How would I comply with the standard?

There are two ways in which you could show compliance with the diurnal standard. First,

you could build all of your boats to have emission rates at or below of 1.1 grams per

gallon. Second, you could choose to comply with this standard on average using various

technologies. In either case, you would need to certify your emissions to EPA. For the

permeation standards, all of your fuel tanks and hoses would have to have emission rates

lower than the proposed standards.

How do I certify?

The Clean Air Act specifies that certification must be based on emission test data. Our

program calls for a manufacturer to measure emissions from its fuel system according to

new test procedures that we are proposing. These test procedures include separate methods for measuring diurnal emissions, tank permeation, and hose permeation. However, we

realize that few of the potentially affected manufacturers would have the ability to build

their own test facilities and conduct their own emission testing. That is why we are

proposing to allow manufacturers to use test data collected by EPA and others for selected marine evaporative emission control technologies. To use this data, you would only

need to demonstrate that emission controls are sufficiently similar to the ones that we

have already tested.
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Which technologies has EPA tested?

We have tested several evaporative emission control technologies that we believe will be

used by manufacturers to meet our marine evaporative emission standard. These include

pressurized fuel tanks, insulated fuel tanks, and fuel bladders. We plan to continue

testing and retesting these technologies during 2002 so that we have a reliable database

when the Final Rule is published. We will also continue testing permeation barriers for

fuel tanks and hoses prior to the Final Rule and any new technologies that are identified.

What technologies could be used to meet the new standards?

Each of the technologies being tested has some defining characteristics, as described

below. If you can show that your controls have the same characteristics, then you can use

the data we already have to show that you meet emission standards.

• Nonpermeable tanks and hoses - We presume that metal tanks and hoses are

nonpermeable, and that plastic tanks are permeable. However, we are aware that

there are plastic tanks and rubber hoses that have very low permeability, especially

those with some sort of a permeation barrier. Thus, you could certify a plastic tank

or rubber hose as nonpermeable, if you can provide an appropriate data and technical analysis.

• Pressurized tanks with pressure-relief valves - The defining characteristics for

pressurized tanks are the pressure at which the relief valve opens, and how it works.

The system we tested works by remaining sealed until the tank pressure reaches the

vent pressure, and then maintains a constant tank pressure by slowly bleeding

pressure.

• Insulated tanks - This approach works by minimizing the daily temperature change.

The defining characteristic is the number of degrees that the fuel temperature

changes when the insulated tank is exposed to the test temperature cycle in an

enclosed environment compared to an uninsulated tank. Thus, you could use emission test data if you could show that your insulation works to keep the temperature

change from exceeding the temperature change observed in our test.

• Bladder tanks - We tested a sealed bladder tank. All bladder tanks that are sealed

should not have measurable diurnal emissions. However, a bladder tank that is

vented can have significant emissions. Therefore, based on our current test data,

only sealed bladder tanks would be needed.

• Volume-compensating air bladders - The most critical characteristic for this system

is the ratio of the volume of the air bladder to the vapor volume of the fuel tank.

However, since these systems require small pressures or vacuum within the tank to

open and close the bladder, the pressure relief system is also important.
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What else would I need to do to certify?

In addition to providing test data, the proposed regulations would require that you submit

an application for certification annually, and that you maintain records of your products

for eight years.

How does this affect small businesses?

Many fuel tank manufacturers are small businesses. We incorporated provisions for small

businesses into the proposal. It includes ample lead time, a number of technology options

for compliance with the proposed requirements, and a set of flexibilities to ease certification and compliance after the rule is implemented.

Are there potential safety implications?

EPA consulted with the U.S. Coast Guard (USCG) throughout the development of this

proposal. A key aim of our approach has been to develop technology options for both

permeation and diurnal control which will meet USCG regulatory requirements and be

safe in use. We will continue to consult with USCG on safety issues related to potential

control technology and requirements throughout the rulemaking.

How can I comment on the proposed rule?

We welcome your comments on the proposed rule. You may submit comments by sending an E-mail to mcnprm@epa.gov, or, for more detailed instructions on submitting

written comments, please see the Federal Register notice. It is available from the EPA

Air Docket by calling (202) 566-1742; please refer to Docket No. A-2000-02. In addition, you can access the Federal Register notice and related documents electronically on

our Web page for recreational marine issues at: www.epa.gov/otaq/marinesi.htm.

Where can I get more information?

Keep an eye on our web page for more information and developments. For further

information, please contact Mike Samulski at:

U.S. Environmental Protection Agency

Office of Transportation and Air Quality

2000 Traverwood Drive

Ann Arbor, MI 48105

E-mail: samulski.michael@epa.gov