# Biological Agent **Entity class:** Statutory biological-weapons concept Under 18 U.S.C. §178, a **biological agent** is a microorganism, infectious substance, or specified naturally occurring, bioengineered, or synthesized component capable of causing defined biological, material, or environmental harm. Ideology and human beings are not included merely because they are biological or transmissible in ordinary language. ## Relationships [[wiki/Vector (Biological Weapons Law)|Vector under biological-weapons law]] · [[wiki/WMD Delivery System|WMD Delivery System]] · [[wiki/Weapon of Mass Destruction|Weapon of Mass Destruction]] ## Sources - [18 U.S.C. §178 — biological-weapons definitions](https://uscode.house.gov/view.xhtml?edition=2023&num=0&req=granuleid%3AUSC-2023-title18-section178) **As of:** 2026-09-23