21 CFR § 510.209 - Establishment, denial, or amendment of an import tolerance.

---
identifier: "/us/cfr/t21/s510.209"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "21 CFR § 510.209 - Establishment, denial, or amendment of an import tolerance."
title_number: 21
title_name: "Food and Drugs"
section_number: "510.209"
section_name: "Establishment, denial, or amendment of an import tolerance."
chapter_name: "FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES"
subchapter_number: "E"
subchapter_name: "ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS"
part_number: "510"
part_name: "NEW ANIMAL DRUGS"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "21 U.S.C. 321, 331, 351, 352, 353, 360b, 371, 379e."
regulatory_source: "40 FR 13807, Mar. 27, 1975, unless otherwise noted."
cfr_part: "510"
---


# 510.209 Establishment, denial, or amendment of an import tolerance.

(a) If an import tolerance is established or amended, the Commissioner will provide public notification of the action, which will be effective from the date of public notification. A copy of the notification will be sent to any requestor at the time the information is made available to the public.

(b) If a request to establish or amend an import tolerance is denied, a notification of the denial will be made publicly available, and a copy of the denial letter, including the reasons for such action, will be sent to the requester.

(c) A tolerance established in an approved NADA or conditionally approved CNADA will supersede an existing import tolerance. In the event the conditionally approved CNADA is not renewed or is withdrawn, or such drug does not achieve approval under section 512 of the Federal Food, Drug, and Cosmetic Act within 5 years following the date of the conditional approval, the Agency will reinstate the import tolerance unless § 510.210(a)(1) or (a)(2) is applicable at that time.