This form must be prepared by the importer for each imported stationary, nonroad or heavy-duty highway engine, including engines incorporated into

vehicles or equipment. Note that references in this form to engines generally include vehicles or equipment if they are subject to equipment-based 

standards. One form per engine or group of engines in a shipment may be used, with attachments including all information required to fully describe 

each engine as below. Provide a duplicate form and attachments to the U.S. Customs and Border Protection (CBP) upon request (42 U.S.C. 7522, 

7601, 19 CFR 12.73 or 12.74). This form must be retained for five years from the date of entry (19 CFR 163.4). Additional requirements may apply in 

California. NOTE: While certain imports require specific written authorization from EPA, CBP may request EPA review of importer documentation and 

eligibility for any import using this form. For light-duty motor vehicles, highway motorcycles, and the corresponding engines, use form 3520-1. This form 

does not apply to aircraft engines.

United States Environmental Protection Agency Engine Declaration Form

Importation of Engines, Vehicles, and Equipment Subject to Federal Air Pollution Regulations

U.S. EPA, Compliance Division, 2000 Traverwood Dr., Ann Arbor, Michigan 48105. (734) 214-4100; imports@epa.gov; www.epa.gov/otaq/imports/

Identify the type of highway, nonroad, or stationary engine, vehicle, or equipment you are importing from the following list of products:

o A. Heavy-duty highway engines (for use in motor vehicles with gross vehicle weight rating above 8500 pounds). See 40 CFR parts 85 and 86.

o B. Locomotives or locomotive engines. See 40 CFR parts 1033 and 1068.

o C. Marine compression-ignition engines. See 40 CFR part 94 or 40 CFR parts 1042 and 1068. This includes propulsion engines and auxiliary 

engines installed on marine vessels.

o D. Other nonroad compression-ignition engines. See 40 CFR part 89 or 40 CFR parts 1039 and 1068.

o E. Marine spark-ignition engines. See 40 CFR parts 1045 and 1068.

o F. Recreational engines and vehicles, including snowmobiles, off-highway motorcycles, all-terrain vehicles, and offroad utility vehicles that are subject 

to the same emission standards as all-terrain vehicles. See 40 CFR parts 1051 and 1068. 

o G. Other nonroad spark-ignition engines at or below 19 kW (or at or below 30 kW if total displacement is at or below 1000 cc). See 40 CFR part 90 

or 40 CFR parts 1054 and 1068.

o H. Other nonroad spark-ignition engines above 19 kW. See 40 CFR parts 1048 and 1068.

o I. Stationary compression-ignition engines. See 40 CFR part 60, subpart IIII.

o J. Stationary spark-ignition engines. See 40 CFR part 60, subpart JJJJ.

Check one of the following Codes to indicate the provision under which you are importing the engine, vehicle, or equipment: 

o 1. U.S. certified engine or engine installed in a certified vehicle, covered by a valid U.S. EPA certificate of conformity and bearing a U.S. EPA 

emission control label in English. Additional information for Category G engines from 2010 and later model years, starting January 1, 2010 (see 40 CFR 

90.1007 or 1054.690): Exempt from bond?___. If not exempt, NAIC # for bond issuer:_____, policy number:____________, state of issue:__.

Permanent Exemptions for Nonconforming Engines

o 2. National security. Importing a labeled (where applicable) engine subject to the provisions of 40 CFR 1068.315(a), 85.1511(c)(1), 89.611(c)(1), 

90.612(c)(1), or 94.804(c)(1). For certain types of tactical equipment, this exemption may require prior EPA approval.

o 3. Manufacturer-owned engine. Importing a labeled engine by an engine manufacturer holding a current U.S. EPA certificate of conformity, subject 

to the provisions of 40 CFR 1068.315(b), 85.1706, 89.906, 90.906, or 94.906.

o 4. Replacement engine. Importing a labeled engine by an engine manufacturer holding a current U.S. EPA certificate of conformity subject to the 

provisions of 40 CFR 1068.315(c), 85.1714, 89.1003(b)(7), 90.1003(b)(5), or 94.1103(b)(3). This exemption does not apply to locomotive engines.

o 5. Extraordinary circumstances/hardship. Importing a labeled engine subject to the provisions of 40 CFR 1068.315(d), 85.1511(c)(2),89.611(c)(2), 

90.612(c)(2), or 1033.620. An EPA letter of approval must be attached.

o 6. Hardship for small-volume manufacturers. Importing a labeled engine subject to the provisions of 40 CFR 1068.315(e) or 94.209(b). An EPA 

letter of approval must be attached to this form.

o 7. Equipment-manufacturer hardship. Importing a labeled engine subject to the provisions of 40 CFR 1068.315(f), 89.102(f), or 94.209(b), or 

1033.620. This may also apply to secondary engine manufacturers. An EPA letter of approval must be attached to this form.

o 8. Identical configuration. Importing an engine subject to the provisions of 40 CFR 1068.315(h), 89.611(c)(3), or 90.612(c)(3). Such an engine must 

be identical in all material respects to a U.S.-certified version as demonstrated by letter from the engine-manufacturer contact on the CBP list, subject 

to EPA review at CBPs’ discretion. This exemption does not apply to locomotives or to stationary, highway, or marine compression-ignition engines. The 

applicable regulations may require that you own the engine for a certain period before and after importation.

o 9. Ancient engine. Importing an engine first manufactured at least 21 years earlier that is still in its original configuration, subject to the provisions of 

40 CFR 1068.315(i), 89.611(f)(2), or 90.612(f)(2). This exemption does not apply to locomotives or to stationary, highway, or marine engines.

Temporary Exemptions for Nonconforming Engines

The following temporary exemptions apply for importing nonconforming engines. EPA requests bonding with the U.S. Customs and Border 

Protection for the full value of the imported products to make sure you comply with applicable requirements.

o 10. Repairs or alterations. Importing an engine for repair or alteration subject to the provisions of 40 CFR 1068.325(a), 85.1511(b)(1), 89.611(b)(1), 

90.612(b)(1), or 94.804(b)(1). An EPA letter of approval must be attached.

o 11. Testing. Importing an engine for testing subject to the provisions of 40 CFR 1068.325(b), 85.1511(b)(2), 89.611(b)(2), 90.612(b)(2), or 

94.804(b)(2). Appropriate labeling is required for some engines and recommended for all engines. An EPA letter of approval must be attached.

o 12. Display. Importing an engine for display subject to the provisions of 40 CFR 1068.325(c), 85.1511(b)(4), 89.611(b)(4), 90.612(b)(3), or 

94.804(b)(3). Appropriate labeling is required for some engines and recommended for all engines. An EPA letter of approval must be attached.

o 13. Export. Importing an engine for eventual export, subject to the provisions of 40 CFR 1068.325(d), 85.1709, 89.909, 90.909, or 94.909. 

NOTE: The engine and/or shipping container must be labeled or tagged to identify them as solely for export.

o 14. Diplomatic or military. Importing an engine subject to the provisions of 40 CFR 1068.325(e), 85.1511(d), 89.611(d), or 90.612(d). This 

exemption is limited to members of the armed forces or personnel of a foreign government on assignment to the U.S. for whom free entry has been 

authorized in writing by the U.S. Department of State, or for members of the armed forces of a foreign country with official orders for duty in the U.S. 

This exemption does not apply to locomotive or marine compression-ignition engines. An EPA letter of approval may be required.

o 15. Delegated assembly. Importing a labeled engine for delegated assembly subject to the provisions of 40 CFR 1068.325(f), 85.1713, or 1033.630. 

This exemption does not apply to handheld spark-ignition engines or engines for recreational vehicles.

o 16. Partially complete engine. Importing an engine not yet in its final configuration covered by a certificate of conformity (or an engine that will be 

installed in a vehicle covered by a certificate of conformity), subject to the provisions of 40 CFR 1068.325(g). This also applies to an engine covered 

by a valid exemption. A certificate holder may also import a partially complete engine from its foreign facility to its U.S. facility as described in 40 CFR 

1068.325(g).

EPA Form 3520-21 (Rev. 01-2014). This form approved under OMB control number 2060-0320 until Dec. 31, 2014. CBP entry no: Pg 1 of 2

Format: XXX- 9 999999-9 ___ _______ _
Importation of Engines Excluded from U.S. EPA Emission Standards

o 17. Engine manufactured before emission standards started to apply. These engines must generally have already been placed into service.See 

the attached schedule. Note that 40 CFR 1068.360 disallows importation of new engines not certified to current standards if the model year is more than 

one year before the year of importation.

o 18. Competition engine. The engine must be used solely for competition, subject to the provisions of 40 CFR 1068.310(a), 85.1511(e), 89.611(e), 

90.612(e), or 94.804(c)(2). An EPA letter of approval must be attached.

o 19. Stationary compression-ignition engine with displacement at or above 30 liters per cylinder or stationary spark-ignition engine above 

19 kW that is not designed to run on gasoline or, if rich-burn, on liquified petroleum gas. These stationary engines are subject to EPA emission 

standards under 40 CFR Subparts IIII and JJJJ, but are not required to be certified. The engine must be used in a stationary manner. See 40 CFR 

60.4219, 60.4248 and 1068.310(b). The engine must be labeled as described in 40 CFR 1039.20 or 1048.20, as applicable. NOTE: Stationary engines 

may be subject to state or local regulations.

o 20. Underground mining. Engine must be used in underground mining and regulated by the Mining Safety and Health Administration (MSHA). See 

40 CFR 89.1 and 1039.5; see also 30 CFR parts 7, 31, 32, 36, 56, 57, 70, and 75. For compression-ignition engines only.

o 21. Hobby engine. Engine must be used to power a reduced-scale model of a vehicle not capable of transporting a person. See 40 CFR

1068.310(c), 89.1(b)(5), and 90.1(d)(6).

Exemptions for Specific Engine Categories or Other Special Cases

o 22. Transition Program for Equipment Manufacturers. Importing a piece of equipment, subject to the provisions of 40 CFR 89.102 or 40 CFR 

1039.625 and 1039.626 (Category D) or 40 CFR 1054.625 and 1054.626 (Category G, 2011 through 2014). Maximum engine power (only for compression-ignition engines): ____________ o kW o HP (or identify the regulatory power category). Exempt from bond?____. If not exempt, NAIC # for bond 

issuer:____________, policy number:____________, state of issue:___.

o 23. Personal-use exemption for small spark-ignition engines. Importing three or fewer nonroad spark-ignition engines at or below 19 kW for 

purposes other than resale, where the importer has not used this exemption in the previous five years, subject to the provisions of 40 CFR 1054.630. 

24. Engine imported by an Independent Commercial Importer recognized by EPA. Only for Categories A and D above. 

o 24a. For modification under an EPA certificate issued for the specific make, model, and model year under 40 CFR 85.1505, 89.605 or 1039.660. 

o 24b. For modification and testing according to 40 CFR 85.1509, 89.609, or 1039.660. NOTE: The imported engine must be at least 6 years old. 

o 24c. For precertification testing to obtain an EPA certificate under 40 CFR 85.1511(b)(3), 89.611(b)(3), or 1039.660. NOTE: CBP bond is required. 

Specify location of storage (required for 24a and 24b): ___________________________________________________________________________

NOTE: Under 24a and 24b, you may import up to five highway engines and five nonroad engines in a given model year that are certified to standards 

based on an engine’s original production year. You may import any number of engines certified to standards that apply based on the year the engine is 

modified. See 40 CFR 85.1503 and 89.603.

o 25. Other exemption. Describe the exemption, attach EPA approval (if applicable), and identify the regulatory cite:

EPA Form 3520-21 (Rev. 01-2014). This form approved under OMB control number 2060-0320 until Dec. 31, 2014. Pg 2 of 2

Declaration of Stationary, Nonroad or Heavy-duty Highway Engine, Nonroad Vehicle or Equipment, or Stationary Equipment

Port code: CBP entry no: Entry date: Engine manufacturer; model and serial number of each engine; for certified engines or 

vehicles, also identify the engine family name:

Identify the engine (or vehicle) build date: 

_____month_______year o on engine o other (explain)

Vehicle or equipment manufacturer; model, serial number, and type of equipment 

(if applicable):

EPA exemption number, required for codes 10, 11, 12, 18:

Names, Addresses, and Telephone Numbers of Relevant Parties

Certification: I certify that I have read and understand the purpose of this form, the penalties for falsely declaring information, for providing 

misleading information, or for concealing a material fact. The information I have provided is correct, and all required attachments are appended to 

this form. I authorize EPA Enforcement Officers to conduct inspections or testing permitted by the Clean Air Act. I am the owner, the importer, or an 

agent of the owner or importer.

Signature: Printed name: Date:

Identify the name, address, phone number, and e-mail address for the importer, broker, and owner as applicable:

Importer (required): Broker (optional): Owner (optional):

Format: 9 999 ____ Format: XXX- 9 999999-9 ___ _______ _

Format: mm/dd/yyyy _ _ _ _ ____

Format: mm/dd/yyyy _ _ _ _ ____
Penalties: (1) Anyone who knowingly makes any false or fraudulent statement, or omits or conceals a material fact can be fined up to $270,000 or imprisoned for up to 5

years, or both (18 U.S.C. 1001). Anyone who illegally imports an engine may be fined up to $32,500 per engine (42 U.S.C. 7524), and may be subject to forfeiture of the

entire importation bond, if applicable (40 CFR 1068.335, 89.612, 90.613, 94.805), and the engine is subject to seizure by CBP (19 CFR 162.21). (2) Anyone who

distributes in commerce, sells, offers for sale, or introduces into commerce an engine subject to EPA certification requirements but not covered by a certificate of

conformity, may be fined up to $32,500 per violation (40 CFR 1068.101(a), 89.1006, 90.1006, 94.1106). (3) Any person who circumvents or attempts to circumvent

residence-time requirements for stationary engines may be fined up to $32,500 per day of violation (40 CFR 1068.101(b)(3), 89.1006(a)(5), 90.1006(a)(5)). 

Information collection: This information is collected to ensure that engines imported into the U.S. conform with applicable emission requirements. Responses to this

collection are mandatory (Clean Air Act sections 202, 203, and 208). Information submitted to the Agency under a claim of confidentiality will be safeguarded as

described in 40 CFR part 2. The public reporting and recordkeeping burden for this collection of information is estimated to average 30 minutes per response. An agency

may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it displays a currently valid OMB control number. Send

comments on the Agency's need for this information, the accuracy of the provided burden estimates, and any suggested methods for minimizing respondent burden,

including through the use of automated collection techniques to the Director, Collection Strategies Division, U.S. Environmental Protection Agency (2822), 1200

Pennsylvania Ave., NW, Washington, DC 20460. Include the OMB control number in any correspondence. Do not send the completed form to this address.

Schedule for Application of New Emission Standards for Certifying Engines and Vehicles

Engine category Engine subcategory Manufacturing date after which

emission standards start to apply

A. Heavy-duty highway engines — Model year 1970

B. Locomotives or locomotive engines — January 1, 1973

C. Marine compression-ignition engines at or

above 37 kW

Commercial: displacement < 0.9 L/cyl Model year 2005

Commercial: 0.9 < displacement < 2.5 L/cyl Model year 2004

Commercial: displacement > 2.5 L/cyl Model year 2007

Recreational: displacement < 0.9 L/cyl Model year 2007

Recreational: 0.9 < displacement < 2.5 L/cyl Model year 2006

Recreational: 2.5 < displacement < 5.0 L/cyl Model year 2009

D. Other nonroad compression-ignition engines. Marine compression-ignition engines: Power < 19 kW January 1, 2000

Marine compression-ignition engines: 19 kW < Power < 37 January 1, 1999

Nonroad engines: Power < 19 kW January 1, 2000

Nonroad engines: 19 kW < Power < 37 January 1, 1999

Nonroad engines: 37 kW < Power < 75 January 1, 1998

Nonroad engines: 75 kW < Power < 130 January 1, 1997

Nonroad engines: 130 kW < Power < 560 January 1, 1996

Nonroad engines: Power > 560 kW January 1, 2000

E. Marine spark-ignition engines. Outboard Model year 1998

Personal watercraft Model year 1999

Sterndrive/inboard Model Year 2010

F. Recreational spark-ignition engines and

vehicles

— Model year 2006

G. Other nonroad spark-ignition engines at or

below 19 kW

— Model year 1997

H. Other nonroad spark-ignition engines above

19 kW

— Model year 2004

I. Stationary compression-ignition engines — April 1, 2006

J. Stationary spark-ignition engines All engines with maximum engine power < 19 kW

Non-emergency engines with maximum engine power between 19

and 373 kW

July 1, 2008

Non-emergency engines with maximum engine power > 373 kW July 1, 2007

Emergency engines with maximum engine power > 19 kW January 1, 2009
Decision flowchart for vehicles

1. Is it a motor vehicle?

§85.1703: A vehicle which is self-propelled and capable of

transporting a person or persons or any material or any

permanently or temporarily affixed apparatus shall be deemed

a motor vehicle, unless any one or more of the criteria set forth

below are met, in which case the vehicle shall be deemed not a

motor vehicle:

! The vehicle cannot exceed a maximum speed of 25

miles per hour over level, paved surfaces; or

! The vehicle lacks features customarily associated

with safe and practical street or highway use, such

features including, but not being limited to, a reverse

gear (except in the case of motorcycles), a

differential, or safety features required by state and/or

federal law; or

! The vehicle exhibits features which render its use on

a street or highway unsafe, impractical, or highly

unlikely, such features including, but not being

limited to, tracked road contact means, an inordinate

size, or features ordinarily associated with military

combat or tactical vehicles such as armor and/or

weaponry. 

-If yes, 40 CFR parts 85 and 86 apply.

-If not, see #2.

2. Is it an off-highway motorcycle or snowmobile?

§1051.801: Off-highway motorcycle means a two-wheeled

vehicle with a nonroad engine and a seat (excluding marine

vessels and aircraft). (Note: highway motorcycles are

regulated under 40 CFR part 86.)

§1051.801: Snowmobile means a vehicle designed to operate

outdoors only over snow-covered ground, with a maximum

width of 1.5 meters or less.

-If yes, part 1051 applies. Note that §§1051.605 and

1051.610 allow for vehicles or engines to be certified

under part 86 or 1048. Note also that diesel-fueled

engines used with off-highway motorcycles or

snowmobiles may be certified under part 89 or 1039

under the provisions of §1051.5.

-If not, see #3.

3. Is it an offroad utility vehicle?

§1051.801: Offroad utility vehicle means a nonroad vehicle

that has four or more wheels, seating for two or more persons,

is designed for operation over rough terrain, and has either a

rear payload capacity of 350 pounds or more or seating for six

or more passengers. Vehicles intended primarily for

recreational purposes that are not capable of transporting six

passengers (such as dune buggies) are not offroad utility

vehicles. (Note: §1051.1(a) specifies that some offroad utility

vehicles are required to meet the requirements that apply for

all-terrain vehicles.)

-If yes, see #4. 

-If not, see #5.

4. Is the offroad utility vehicle subject to part 1051?

§1051.1(a)(4) Offroad utility vehicles with engines with

displacement less than or equal to 1000 cc, maximum engine

power less than or equal to 30 kW, and maximum vehicle

speed higher than 25 miles per hour. Offroad utility vehicles

that are subject to this part are subject to the same

requirements as ATVs. This means that any requirement that

applies to ATVs also applies to these offroad utility vehicles,

without regard to whether the regulatory language mentions

offroad utility vehicles. 

-If yes, part 1051 applies. Note that §§1051.605 and

1051.610 allow for vehicles or engines to be certified

under part 86 or 1048. Note also that diesel-fueled

engines used with offroad utility vehicles may be

certified under part 89 or 1039 under the provisions of

§1051.5.

-If not, see #6.

5. Is it an all-terrain vehicle?

§1051.801: All-terrain vehicle means a land-based or

amphibious nonroad vehicle that meets either of the following

criteria:

(1) Vehicles designed to travel on four low pressure tires,

having a seat designed to be straddled by the operator and

handlebars for steering controls, and intended for use by a

single operator and no other passengers are all-terrain vehicles.

(2) Other all-terrain vehicles have three or more wheels and

one or more seats, are designed for operation over rough

terrain, are intended primarily for transportation, and have a

maximum vehicle speed of 25 miles per hour or higher. Golf

carts generally do not meet these criteria since they are

generally not designed for operation over rough terrain. 

NOTE: Amphibious vehicle means a vehicle with wheels or

tracks that is designed primarily for operation on land and

secondarily for operation in water. 

-If yes, part 1051 applies. Note that §§1051.605 and

1051.610 allow for vehicles or engines to be certified

under part 86 or 1048. Note also that diesel-fueled

engines used with all-terrain vehicles may be certified

under part 89 or 1039 under the provisions of §1051.5.

-If not, see #6.

6. Does it have a spark-ignition engine?

§1054.801: Spark-ignition means relating to a gasoline-fueled

engine or any other type of engine with a spark plug (or other

sparking device) and with operating characteristics

significantly similar to the theoretical Otto combustion cycle. 

Spark-ignition engines usually use a throttle to regulate intake

air flow to control power during normal operation. 

-If yes, see #7.

-If not, it is subject to standards for diesel engines

(marine, locomotive, or other land-based nonroad).

7. Is it a marine vessel?

§1054.801: Marine vessel has the meaning given in 1 U.S.C.

3, except that it does not include amphibious vehicles

[See #5]. The definition in 1 U.S.C. 3 very broadly includes

every craft capable of being used as a means of transportation

on water.

-If yes, part 1045 applies.

-If not, the engine is subject to standards for Small SI or

Large SI engines, depending on the maximum engine

power and total displacement.