21 CFR § 573.340 - Diatomaceous earth.

---
identifier: "/us/cfr/t21/s573.340"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "21 CFR § 573.340 - Diatomaceous earth."
title_number: 21
title_name: "Food and Drugs"
section_number: "573.340"
section_name: "Diatomaceous earth."
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: "573"
part_name: "FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS"
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, 342, 348."
regulatory_source: "41 FR 38652, Sept. 10, 1976, unless otherwise noted."
cfr_part: "573"
---


# 573.340 Diatomaceous earth.

(a) *Identity.* The additive consists of siliceous skeletal material derived from various species of diatoms.

(b) *Specifications.* The additive shall conform to the following specifications:

Lead, not more than 15 parts per million.

Arsenic (as As), not more than 20 parts per million

Fluorine, not more than 600 parts per million.

(c) *Uses.* It is used or intended for use as an inert carrier or anticaking agent in animal feeds in an amount not to exceed 2 percent by weight of the total ration.