Vehicles and animals · EPA
EPA Form 3520-21: Declaration for imported engines, vehicles and equipment (emissions)
EPA Form 3520-21 is the emissions declaration for engines, and for vehicles and equipment that contain them. Examples are generators, construction machines, boats, ATVs and heavy trucks.
At a glance
- Issued by
- U.S. Environmental Protection Agency
- Rules
- 40 CFR Part 1068 and the parts listed on the form
- Who signs
- The importer
- Records
- Keep for 5 years from the date of entry
- Current edition
- August 2024
EPA Form 3520-21
What is EPA Form 3520-21?
EPA Form 3520-21 is the EPA declaration for stationary, nonroad and heavy-duty highway engines. It also applies to engines already installed in vehicles or equipment.
The importer selects the product type, for example heavy-duty highway (generally over 14,000 pounds GVWR), marine, recreational vehicles or small spark-ignition engines.
Then the importer selects the code for the basis of import. Code 1 is a U.S.-certified engine with an EPA label in English.
Who and when
Who needs it and when?
- Importers of machinery, generators, outboard motors, ATVs, off-highway motorcycles, and heavy-duty trucks or engines.
- New products imported by the original maker with an EPA certificate and label do not need it (form text).
- Aircraft engines are not covered. Light-duty vehicles and highway motorcycles use EPA Form 3520-1.
Roles
Who signs it and who files it?
- The importer signs the declaration. One form can cover one engine or a group of engines in a shipment, with attachments.
- Your broker files it with the entry. EPA explains electronic filing through ACE on its forms page.
- Keep the form for 5 years from the date of entry (19 CFR 163.4).
Avoid delays
What mistakes delay it?
No EPA label on the engine
Code 1 needs a valid EPA certificate and an emission label in English.Bond details missing for small engines
For small spark-ignition engines (category G), the form asks if you are exempt from the bond, or for the bond details.The vehicle form instead of this one
Light-duty vehicles and highway motorcycles use Form 3520-1. Everything else with an engine usually uses Form 3520-21.State rules ignored
The form notes that more requirements can apply in California.
Official source
Where do I get the official form?
EPA's forms page has the current fillable PDF and a summary of the codes.
- Official pageEPA: Publications and Forms for Importing Vehicles and Engines (opens in a new tab)
- Current formEPA Form 3520-21 (PDF, epa.gov) (opens in a new tab)
Edition checked on September 26, 2026: EPA Form 3520-21, August 2024. We link to the official source and do not host copies, because agencies replace forms without notice.
Allied CHB
How can Allied help with EPA Form 3520-21?
We check the product type and code before the machine or engine ships, then file the 3520-21 with the entry.
Allied CHB is a licensed U.S. customs broker in Rahway, New Jersey, CBP filer code 9AJ. We file at all U.S. ports of entry.
Vehicle and engine imports Entries with the EPA and DOT declarations filed correctly.
Request: Help with EPA Form 3520-21
Quote on request
Questions
What else do people ask about EPA Form 3520-21?
Does a used excavator need Form 3520-21?
Yes, for its nonroad engine. You declare the basis of import for the engine, even when the machine is used.
Does a generator need it?
Yes. Generator engines are stationary or nonroad engines, which the form covers.
What if the engine is not EPA-certified?
The form lists limited exemptions, for example national security, hardship or identical configuration. Some need an EPA letter. Otherwise the engine does not qualify.
Need help with EPA Form 3520-21?
Call (908) 291-8001 or email info@alliedchb.com
Last reviewed September 26, 2026. This page explains customs rules in general terms. It is not legal advice. Duty rates and CBP procedures change often, and we confirm the figures for your shipment in writing before you commit.