Last updated: Nov 27, 2025
Key Takeaways
- ACE HTS flags are binary triggers: they are either Conditional (allowing a 'Not Regulated' disclaim) or Mandatory (requiring full data), with no middle ground for Fatal flags like FD4.
- The 'Trigger and Satisfy' architecture requires specific Disclaim Codes (A, B, C, D) in the PG01 record; misusing Code A on a Fatal Flag results in immediate PX22 rejection.
- Successfully clearing the PGA Message Set requires precise data mappingâsuch as FDA Product Codes or EPA Certificate Numbersâthat aligns strictly with the HTS flag's programmed severity.
1. Overview
The Automated Commercial Environment (ACE) functions as the definitive "Single Window" for the United States' international trade processing ecosystem. Within this architecture, the Harmonized Tariff Schedule (HTS) flagging system serves as the primary validation triggerâa complex, hard-coded logic layer that dictates the strict admissibility requirements for every commodity entering U.S. commerce.
This technical reference provides an exhaustive analysis of the logic, syntax, and data schemas enforced by these flags. It serves as the ground truth for compliance officers and customs brokers navigating the ACE CATAIR (Customs and Trade Automated Interface Requirements), delineating exactly when data is strictly mandatory versus when a disclaimer is legally permissible.
2. Key Concepts
The interaction between a submitted HTS code and the resulting Partner Government Agency (PGA) Message Set requirement is deterministic, governed by a rigid "Trigger and Satisfy" architecture. Understanding this hierarchy is essential for successful entry transmission.
ACE Flag Severity Levels
- Conditional Flags (Warning): Indicators such as
FD1(FDA),AQ1(APHIS), orDT1(NHTSA) suggest potential regulatory interest. The system logic permits two distinct pathways: submission of the full PGA Message Set (if regulated) or submission of a valid Disclaim Code (e.g., Code 'A') in the PG01 record. - Mandatory Flags (Fatal): Indicators such as
FD4(Food),EP1(EPA Vehicles), orFW3(Wildlife) represent a hard stop. ACE business rules are programmed to reject the entry transmission entirely if the required PGA data is absent. In these scenarios, the option to disclaim is systematically blocked.
PGA Message Set Architecture
- PG01 (Agency Header): The root record declaring the Agency Code (e.g., FDA), Program Code (e.g., FOO), and Processing Code. It houses the critical Disclaim Code field at Position 80.
- PG14 (LPCO Data): The "Licenses, Permits, Certificates, and Other" record. This is the container for affirmative authorization numbers, such as EPA Certificates of Conformity or APHIS Permits.
Disclaim Logic
- Disclaim Code 'A': Strictly defined as "Product is not regulated by this agency." Used only when the HTS is broad (e.g., "Other Chemical") and the specific item is not on the agency's control list.
- Flag-Disclaim Conflict: A critical validation rule where ACE rejects an entry if a filer attempts to use Disclaim Code 'A' on a Fatal Flag (e.g., FD4). If the HTS flags it as "Food," the system considers a claim of "Not Regulated" to be a logical contradiction.
3. Core Principles (Master Flag Matrix)
The following matrix constitutes the definitive technical reference for active HTS flags in the ACE production environment, synthesizing definitions from CATAIR Appendix B and agency-specific Implementation Guides.
| Flag Code | Definition & Agency | Strictness & Logic |
|---|---|---|
| FD1 | FDA: May be regulated | Conditional (Disclaimable). Use Disclaim 'A' if industrial/non-regulated. If regulated, full Message Set required. |
| FD2 | FDA: Regulated (Non-Food) | Strict (Mandatory). Used for Devices/Drugs. Must submit PG23 (Listing/Registration). Disclaimers typically blocked. |
| FD4 | FDA: Food Product | Strict (Fatal). Prior Notice data is absolutely required. No disclaimers allowed. Absence results in immediate rejection. |
| EP1 | EPA: Certificate of Conformity | Strict (Mandatory). Vehicles/Engines. Must submit LPCO Type "COC" and Certificate Number in PG14. |
| EP5 | EPA: Pesticides/Devices (TSCA) | Conditional. Used for pesticidal devices or chemicals. If regulated, Notice of Arrival (NOA) data is required in PG14. |
| DT2 | NHTSA: Motor Vehicle | Strict (Mandatory). Subject to Federal Motor Vehicle Safety Standards. HS-7 data elements (VIN, Make, Model) required. No disclaimers. |
| AQ2 | APHIS: Data Required | Strict (Mandatory). Logic assumes the HTS is specific enough to confirm regulation (e.g., live dogs). Data must be filed. |
| FW3 | FWS: Data Required | Strict (Mandatory). Covers live animals/wildlife products. eDecs confirmation and PGA Message Set required. |
4. Common Issues & Solutions
When HTS flags and submitted data do not align, ACE generates specific error messages. The most pertinent are the PX series errors generated during PGA Message Set syntax validation.
| Error Code | Cause | Solution |
|---|---|---|
| PX13 (MISSING/INVALID AGENCY CODE) | The PG01 record does not contain a valid code (e.g., "FDA", "EPA") recognized by the system. | Verify PG01, Position 8-10. Ensure the code matches Appendix V of the CATAIR. |
| PX22 (INV DATA FOR HTS/PGA FLAG) | The submitted data (or disclaim) contradicts the HTS flag strictness (e.g., Disclaiming an FD4 flag). | Critical Error. You likely disclaimed a Fatal Flag. Either file full data or correct the HTS classification if the product is truly not regulated. |
| PX54 (ITEM NOT ON LISTING) | The LST (Device Listing) or Registration Number provided in PG23 does not exist in the Agency's database. | Verify the number with the manufacturer. Check for typos or inactive status in the FDA Unified Registration Listing Systems (FURLS). |
| Status: DOCUMENTS REQUIRED | Syntax passed, but the Agency requires a physical document (PDF) for review. | Upload the required document (e.g., Mill Test Report) to the Document Image System (DIS) tagged with the correct Agency Document Code (e.g., FWS02). |
5. Quick Reference: Disclaim Codes
Disclaiming is the process of affirmatively stating, "This HTS flag exists, but my product is not subject to the agency's requirements." These codes are submitted in the PG01 record at position 80.
- Code A â Not Regulated. Used when the HTS is broad (e.g., "Other Articles of Plastic") and the specific item is not on the agency's control list. Allowed for FD1, DT1, AQ1.
- Code B â Not Required per Guidance. Used when the product is regulated, but a specific administrative exemption (e.g., de minimis waiver) applies to the data submission.
- Code C â Filed via Other Means. Indicates data was submitted via a separate portal prior to entry. Warning: Many agencies (FDA, APHIS) have removed acceptance of Code C, mandating ACE filing.
- Code D â Filed via Paper. Explicitly for paper submission. Rare and often blocked in a fully automated ACE environment.
6. Interactive Tool
Use the HTS & PGA Flag Checker mini-agent to scan commercial invoices and HTS lists against the logic defined in this matrix. This tool parses the HTS codes from your documents, performs a real-time lookup against the CATAIR Appendix B definitions, and outputs the specific PGA requirements (Mandatory vs. Conditional).
The tool also cross-references your proposed Disclaim Codes against the "Fatal Error" logic to prevent PX22 rejections before transmission.
Validation Tool
HTS & PGA Flag Checker
Scan commercial invoices and HTS lists to identify Partner Government Agency (PGA) triggers and validate disclaim logic.
Cross-references CATAIR Appendix B & PGA Message Set requirements
Flag Analysis Result
Enter HTS codes to identify PGA flags and validate disclaim eligibility.
Demo output only; not a substitute for CBP rulings or legal review.
7. Implementation Guide
To successfully transmit entries with PGA data, filers must map the HTS flag to the specific granular CATAIR records required to achieve a "May Proceed" message. This section details the data mapping for the most common high-volume agencies.
FDA (Food) - FD4 Flag Data Mapping
- PG01 (Header): Must use Program Code "FOO" (Food).
- PG02 (Product): Requires a valid 7-digit FDA Product Code (e.g., 12A-B-34). Mismatches here are the leading cause of rejection.
- PG19/20 (Entity): Unlike other programs, Food requires the identification of the Grower or Consolidator if the manufacturer is unknown, to satisfy Bioterrorism Act tracing.
NHTSA - DT2 Flag Data Mapping
- PG01 (Header): Must use Program Code "MVS" (Motor Vehicle Safety).
- PG02 (Identity): The Item Identity field must contain a valid 17-character VIN (Vehicle Identification Number).
- PG10 (Category): Must define the HS-7 "Box" number (e.g., Box 1 for Conforming, Box 3 for Non-Conforming).
- PG14 (LPCO): If Box 3 (Non-Conforming) is selected, the Registered Importer (RI) Number and Contract Number are strictly mandatory.
EPA (Vehicles) - EP1 Flag Data Mapping
- PG01 (Header): Must use Program Code "VNE" (Vehicles and Engines).
- PG14 (LPCO): Critical record. Must file LPCO Type "COC" followed by the valid EPA Certificate of Conformity Number.
- Logic Trap: If importing under an exemption (e.g., Racing), you must often provide a Bond Policy Number (Flag EP7) in PG14 or PG25; failure to do so triggers a logic rejection.
8. Additional Resources
- CBP ACE CATAIR: The official technical specifications for all message sets, including the "PGA Message Set" chapter and "Appendix B" for HTS flags.
- FDA Supplemental Guide: Detailed breakdown of the four-program logic (Food, Drugs, Devices, Biologics) and valid Product Code schemas.
- NHTSA Implementation Guide: Specifies the mapping between HS-7 Box numbers and ACE PG10 Category Codes.
Frequently Asked Questions
What is the difference between a Conditional and a Fatal HTS flag?
Conditional flags (e.g., FD1) allow you to disclaim regulation (using Code A) if the product is exempt. Fatal flags (e.g., FD4 for Food, EP1 for Vehicles) block disclaimers entirely, requiring mandatory data submission or immediate rejection of the entry.
How do I resolve a PX22 'Invalid Data for HTS/PGA Flag' error?
A PX22 error typically means you attempted to disclaim a Fatal Flag. You must either provide the full required PGA Message Set data or, if the product is truly not regulated, correct the HTS classification to a code that does not carry the fatal flag.