How have militaries and police regulated ethical testing and deployment of sonic and millimeter‑wave crowd‑control systems?
Executive summary
Militaries and police have approached sonic and millimeter‑wave crowd‑control systems through a patchwork of internal testing protocols, constrained deployments, and legal rationales rather than comprehensive, independent regulation; official claims of compliance with law of armed conflict and domestic policy coexist with documented injuries, limited oversight, and calls for stricter rules from civil‑society groups [1] [2] [3] [4]. In practice this has produced cautious, situational use, contested accountability, and persistent debate over acceptable risk and transparency [5] [6] [7].
1. Legal frameworks and official justifications
Armed forces developing directed‑energy systems frame them as “non‑lethal” options compatible with treaty and domestic legal obligations, with U.S. Army reporting that Active Denial and successor systems were developed to meet law‑of‑war and U.S. policy constraints [1]; military publications and officials routinely argue these technologies fill a gap between lethal force and less‑effective alternatives [5] [8].
2. How testing has been conducted and what it revealed
Testing has been largely internal and incremental: the ADS and Solid‑State ADT programs underwent volunteer trials and demonstrations that produced both demonstration claims of effectiveness and documented injuries — including at least two burn incidents cited in testing histories — underscoring the limits of safety claims [3] [2]. Official reporting highlights technical parameters (95 GHz millimeter waves, shallow skin penetration) used to argue minimized systemic harm, yet public data on long‑term effects remains scarce and largely unpublished by independent bodies [2] [9].
3. Rules of engagement and operational constraints
Operational deployment has been cautious and often restricted by bureaucratic, logistical and political constraints: the large, power‑hungry ADS units have practical deployment limits and have repeatedly been sidelined for hands‑on use despite interest from commanders, while requests to use such systems in domestic protest settings (e.g., the 2020 D.C. protests) drew internal inquiries and public scrutiny rather than clear deployment [8] [6]. Police use of LRAD and other acoustic hailing devices is framed as communication tools, but law‑enforcement guidance and practices vary widely on whether and how “alert tones” may be used for dispersion [4] [10].
4. Civil society, litigation and calls for oversight
Civil‑liberties organizations and human‑rights groups have pushed for moratoria, stronger regulation and independent study: the ACLU urged suspension of LRAD use at protests because of risks and inadequate health research, and Amnesty and other actors have proposed specific guidelines for testing and deployment of acoustic and directed‑energy devices [4] [11]. Activists continue to demand clearer accountability, and independent reporting documents contested uses and legal challenges where LRADs and similar devices have been deployed [7] [12].
5. Technical realities that shape ethical choices
The technical profile of these systems shapes regulation: millimeter waves penetrate only superficially but can cause intense pain and occasional burns, while LRADs can produce decibel levels capable of causing disorientation or permanent hearing damage if misused; those characteristics both justify constrained use and heighten concerns about proportionality and unintended harm [2] [4] [10]. Operational factors — size, power requirements, and proof‑of‑effect versus safety tradeoffs — have also limited widescale fielding and forced a pragmatic, case‑by‑case adoption posture [8] [9].
6. Where oversight falls short and what’s being demanded
The resulting regulatory landscape is fragmented: military units assert internal compliance and target‑specific rules, police agencies adopt varied local policies, and courts or settlements sometimes retroactively constrain behavior [1] [6], but independent, transparent oversight, robust epidemiological study, and uniform deployment standards remain lacking — a gap civil‑society groups explicitly call to close with stricter rules, public reporting, and bans on certain modes of use until safety and accountability benchmarks are met [7] [11] [4].