What are the differences between police, ICE and military rules regarding riot control agents under U.S. and international law?
Executive summary
U.S. rules on riot control agents diverge sharply by actor: the military operates under detailed Department of Defense doctrine and international law instruction, ICE follows DHS use-of-force policies within the federal-law enforcement framework, and local police operate under a patchwork of state statutes and far less uniform regulation — a gap that creates different limits, training requirements, and oversight regimes [1] [2] [3].
1. Legal frameworks: domestic law versus international law
The use of riot control agents is governed domestically by statutes, agency regulations and constitutional limits for law enforcement, while in the military context the Law of Armed Conflict and treaties such as the Geneva Conventions provide additional constraints and training obligations; military personnel who may employ riot control agents are required to receive annual instruction on the Law of Armed Conflict, a requirement reflected in DOD doctrine and directives [1] [1].
2. The military: detailed doctrine and international constraints
U.S. Armed Forces treat riot control agents as regulated weapons with uniform command-level doctrine, annual LOAC training for relevant personnel, and explicit directives governing peacetime and overseas use — a system intended to ensure compliance with both U.S. policy and international law, and to limit employment to circumstances set out in DOD and combatant command guidance [1] [1].
3. ICE: federal agency rules within law-enforcement norms
ICE operates under DHS use-of-force and crowd-control policies that aim to align with constitutional standards — requiring force to be “objectively reasonable” and emphasizing de‑escalation in guidance updated in 2023 — but ICE remains a federal law‑enforcement agency whose actions are judged by federal immunity doctrines, internal policy, and occasional court limits when policies are challenged [4] [5] [6].
4. Local police: state law variability and looser equipment controls
State and local police face a fragmented regulatory environment: many states allow “reasonable” or arrest‑related force with wide interpretive room, training and restrictions on riot-control agents vary by jurisdiction, and there is comparatively little uniform national regulation of police acquisition or use of military-grade equipment and less specific minimum standards than in the military context [3] [3].
5. How the differences play out in practice: training, limits, oversight and immunity
Because the military’s employment of riot agents is embedded in doctrine and LOAC training, its use is typically more centralized and auditable, while ICE relies on DHS policy that can be updated and has been criticized for gaps in recorded training and unclear community engagement consequences; local police may use agents like OC/CS routinely but under uneven standards, producing variability in practices and oversight — and federal actors often have distinct immunity or preemption protections that affect accountability [1] [7] [8] [9].
6. Judicial and civic check: courts, injunctions and advocacy
Courts and civil-rights groups have stepped in where federal deployments raised constitutional concerns, imposing injunctions that limit ICE tactics such as use of chemical irritants or stops without reasonable suspicion, and Human Rights Watch and other organizations have urged Congressional oversight when federal agents’ crowd-control practices appear inconsistent with DHS policy or constitutional protections [10] [11] [12].
7. Bottom line: one set of tools, three different rulebooks
The same tools — OC, CS and other “riot-control” agents — are governed by three different systems: uniform military doctrine and LOAC training for armed forces, DHS policy and federal-law enforcement norms for ICE, and a decentralized, state-by-state mosaic for local police; that structural divergence produces different training obligations, transparency, and legal remedies, and it is the core reason public controversies about chemical irritant use map onto debates over authority, oversight and rights [1] [2] [3].