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Environmental

Fact Sheet

 Printed on Recycled Paper

United States

Environmental Protection

Agency

Air and Radiation EPA420-F-01-029

September 2001

Office of Transportation and Air Quality

Frequently Asked Questions:

Emission Standards for

Recreational Marine Diesel Engines

In September 2001, the U.S. Environmental Protection Agency (EPA)

published a Notice of Proposed Rulemaking (NPRM) to seek public

comment on our plan to propose more stringent emission standards for

engines on equipment including forklifts and generators, and vehicles

including snowmobiles, off-highway motorcycles and ATVs, and recreational marine diesel engines. This information sheet addresses common

questions we have heard from concerned parties.

What is a Recreational Marine Diesel Engine?

This proposal applies to diesel engines over 37 kW used for propulsion

on recreational boats. In general, this includes all vessels used “primarily for pleasure,” consistent with Coast Guard policy.

Why is EPA looking at new emission controls for

Recreational Marine Diesel Engines?

We already require emission controls for commercial marine diesel

engines; the recreational engines are capable of using similar emission

control strategies. Our analysis shows that recreational marine diesel

engines emit about 25,000 tons of hydrocarbons plus nitrous oxides

(HC+NOx) each year across the United States. These emissions help
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form smog and contain toxic compounds such as benzene, so reducing

them would benefit our health and environment. The Clean Air Act

requires us to set emission standards that 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].

Must the engine I own meet these regulations?

No. Engine manufacturers must ensure each new recreational marine

diesel engine sold meets our regulations. The proposed regulations

would apply only to new engines produced after a specified model year.

Anything manufactured before that model year would not be affected and

would remain legal to own and operate. We usually allow several years

of lead time between publication of a final rule and the effective date of

new standards. Thus, new standards for recreational marine diesel

engines won’t affect the engine you bought before this year or any engine

you buy for the next several years.

As an owner of a recreational marine diesel engine,

what must I do?

You may not disable any emission controls installed on your engine to

meet our regulations. Manufacturers will explain in their owner’s

manual what type of emission controls exist for each model. Manufacturers may also specify some minor maintenance you must have done to

keep emission controls working properly over the life of the engine.

What kinds of emission controls is EPA considering?

We don’t specify what emission controls manufacturers must use to

comply with the regulations, but we anticipate many manufacturers will

choose to meet them through engine calibration, fuel injection improvements, and in-cylinder modifications.

How much will these controls cost?

Your cost for emission controls depends on the control used, manufacturing processes, the size of the manufacturer, and other issues. With that

said, we do not expect these changes to increase engine costs by more

than two percent.
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How will these controls affect performance and

safety?

These technologies should not only reduce emissions, but improve

engine performance. None of the emission controls we are considering

affect safety.

Will these regulations affect where I can use my

boat?

No. The proposed regulations don’t restrict your use. They cover only

the exhaust emissions from your new engine.

Will EPA publish noise regulations?

We are not proposing any new noise regulations. However, the technologies used to reduce NOx emissions should result in some noise reduction.

Where can I get more information?

Keep an eye on our web page for marine diesel engines (http://

www.epa.gov/otaq/marine.htm) for more information and any developments. You may comment on the issues in this fact sheet or in the Notice

of Proposed Rulemaking (NPRM) by sending an email to

nranprm@epa.gov.

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

samulski.michael@epa.gov