40 CFR § 152.161 - Definitions.

---
identifier: "/us/cfr/t40/s152.161"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 152.161 - Definitions."
title_number: 40
title_name: "Protection of Environment"
section_number: "152.161"
section_name: "Definitions."
chapter_name: "ENVIRONMENTAL PROTECTION AGENCY"
subchapter_number: "E"
subchapter_name: "PESTICIDE PROGRAMS"
part_number: "152"
part_name: "PESTICIDE REGISTRATION AND CLASSIFICATION PROCEDURES"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "7 U.S.C. 136-136y; Subpart U is also issued under 31 U.S.C. 9701."
cfr_part: "152"
---


# 152.161 Definitions.

In addition to the definitions in § 152.3, the following terms are defined for the purposes of this subpart:

(a) *Dietary LC*<sub>50</sub> means a statistically derived estimate of the concentration of a test substance in the diet that would cause 50 percent mortality to the test population under specified conditions.

(b) *Outdoor use* means any pesticide application that occurs outside enclosed manmade structures or the consequences of which extend beyond enclosed manmade structures, including, but not limited to, pulp and paper mill water treatments and industrial cooling water treatments.