What do Department of Defense directives say specifically about domestic use of riot control agents?

1. Legal posture: renunciation of first use in war, with a delegated regulatory carve‑out

An enduring pillar of U.S. policy is Executive Order 11850, which states that the use of riot control agents and chemical herbicides in war is prohibited unless the President gives advance approval and charges the Secretary of Defense to prescribe necessary implementing rules and regulations ^{[1] [4]}. That presidential renunciation is echoed in statutory language and historical codification asserting that the United States renounces first use of such agents in war, while allowing limited exceptions subject to regulations applicable to domestic use and defensive military modes to save lives ^{[2] [5]}.

2. DoD doctrine: narrow operational authorizations tied to specific contexts

DoD doctrine and the Law of War Manual interpret these constraints to permit employment of RCAs in narrow circumstances during armed conflict—specifically, for riot control in areas under direct and distinct U.S. control and in other defensive modes where lives may be saved—rather than as a general battlefield weapon ^[3]. Congressional and DoD testimony and doctrinal materials emphasize training and rules of engagement: personnel authorized to employ RCAs receive instruction on the law of armed conflict and on the permissible circumstances for RCA use ^[6].

3. Peacetime and domestic law enforcement: division between military and civilian roles

International treaty and normative frameworks distinguish domestic law‑enforcement use from warfare: the Chemical Weapons Convention bans RCAs “as a method of warfare” but does permit certain uses for law enforcement including domestic riot control, provided types and quantities are consistent with that purpose—a distinction U.S. policy and some DoD materials have relied upon in justifying limited RCA employment in specific operational scenarios ^[7]. However, the existence of that treaty carve‑out does not collapse the institutional separation: DoD directives and service publications reference internal rules and authorities (e.g., DOD Directive 5210.56 cited in service manuals) governing how military personnel involved in security, law and order activities may carry out force, though those references do not amount to a public, detailed playbook for military domestic crowd control ^{[8] [9]}.

4. Practical constraints, medical and ethical caveats, and interpretive disputes

Medical and humanitarian observers warn that RCAs can cause serious harm if misused—particularly in enclosed spaces—and that their wartime and domestic employments raise distinct ethical and legal issues; the World Medical Association explicitly notes that RCAs are excluded from warfare and their domestic use raises medical, legal and ethical challenges ^[10]. Arms‑control analysts have documented the gray area between domestic law enforcement and warfare use, noting different states’ interpretations (for example, some allies refusing battlefield RCA use), and the Pentagon’s historical practice of requiring careful decision processes and, at times, presidential authorization or delegation for RCA employment in combat zones ^[7].

5. What the public record does not show: gaps in transparent DoD domestic‑use rules

Publicly available sources establish the high‑level limits—presidential approval for wartime use, Secretary of Defense rulemaking, lawful use in narrowly defined operational contexts, and training requirements—but do not publish a single comprehensive, unambiguous DoD directive text that lays out step‑by‑step domestic deployment authority for military units operating within U.S. territory; service manuals cite relevant DoD directives and policies, yet the detailed operational chain of command, thresholds, and coordination with civilian law enforcement in domestic RCA employment are not fully visible in the provided reporting ^{[8] [9]}.

Conclusion

DoD directives and related U.S. policy make clear that riot control agents are not free‑for‑all tools: their first use in war is renounced absent Presidential waiver, DoD doctrine limits military RCA use to narrowly defined situations such as riot control in U.S.‑controlled areas or defensive life‑saving modes, and international law treats domestic law‑enforcement usage differently from warfare—yet significant interpretive gray zones and limited public transparency remain about precise domestic employment procedures and oversight ^{[1] [2] [3] [7] [6] [8]}.