Police less lethal weapons are intermediate force tools — kinetic impact projectiles, conducted energy devices like TASERs, chemical irritants such as pepper spray and tear gas, and distraction devices including flashbangs and long-range acoustic devices — and while they’re designed to incapacitate rather than kill, they regularly cause serious injury and sometimes death. A systematic review in BMJ Open documented 53 deaths and 300 permanent disabilities among nearly 2,000 people struck by kinetic impact projectiles alone. If one of these weapons injures you and the force was objectively unreasonable under the Fourth Amendment, federal law gives you a path to sue the officer and potentially the department.
Kinetic Impact Projectiles
Kinetic impact projectiles are blunt-force rounds fired from specialized launchers: rubber bullets, plastic rounds, and beanbag rounds (fabric pouches filled with small lead pellets). They work by transferring energy on impact, and where they land determines whether someone walks away with a bruise or a permanent injury.
Department policies typically require officers to aim at the lower extremities and avoid the head, neck, and chest. But these projectiles are inherently less precise than conventional rounds, especially at longer distances, and in a chaotic crowd a round aimed at a thigh can strike a bystander in the face. Close range is dangerous for the opposite reason — the projectile hasn’t slowed, and the concentrated energy can fracture bones or penetrate tissue.
The BMJ Open review found that 71% of injuries among survivors were classified as severe. Head and neck strikes accounted for half of all deaths and more than 82% of permanent disabilities. Of 310 documented ocular injuries, roughly 84% resulted in permanent blindness. Many of the projectiles studied had metal cores or metal fragments, which pushed their lethality well beyond what the “rubber bullet” label suggests.
Conducted Energy Devices
Conducted energy devices, widely known by the brand name TASER, use electrical pulses to override voluntary muscle control. The device fires two barbed probes that embed in clothing or skin, creating a circuit across the body. When the probes land at least about 12 inches apart, the current causes involuntary muscle contractions throughout the affected area and the person loses control of their movements for the duration of the cycle. A standard cycle is five seconds.
Officers can also use the device in drive-stun mode by pressing it directly against the body. That mode doesn’t produce full neuromuscular incapacitation; it works through localized pain, which makes it less effective at stopping a determined person but more likely to be used repeatedly out of frustration.
A study published in the American Heart Association’s journal Circulation found that conducted energy device shocks can cause cardiac electrical capture and provoke ventricular fibrillation, a potentially fatal heart rhythm. The risk rises when probes land on or near the anterior chest, when shocks are prolonged or repeated beyond the five-second cycle, and when the subject has an underlying heart condition or is under the influence of certain drugs. All seven cases of sudden cardiac arrest examined in that study involved probes in the chest area of previously healthy men.
For most people, though, the bigger danger isn’t the electricity itself. It’s the uncontrolled fall that follows full incapacitation. Broken bones, dislocated shoulders, and serious head trauma from hitting pavement are common secondary injuries. And when someone is TASED and then restrained in a prone position with pressure on the chest or back, the risk of positional asphyxia rises sharply.
Chemical Irritants: Pepper Spray and Tear Gas
Pepper spray (oleoresin capsicum, or OC) is derived from chili peppers and causes intense burning pain in the eyes, skin, and airways on contact. Tear gas, usually a compound called CS, produces similar effects: inflammation, uncontrollable tearing, coughing, and a sensation of suffocation. Both can be delivered from handheld canisters or launched as grenades and pepper balls for crowd dispersal.
For most people the acute effects resolve within about 30 minutes after exposure ends and the person reaches fresh air. Eye irritation and redness can persist for up to 24 hours. People with asthma or other respiratory conditions face a much higher risk of severe breathing difficulties, and children and the elderly are disproportionately affected.
The CDC notes that large or sustained doses of riot control agents can cause lasting eye damage including glaucoma and cataracts, and chronic breathing problems like asthma. The risk is highest when exposure happens in enclosed spaces where chemical concentration is high and escape is difficult.
Flashbangs and Acoustic Weapons
Flashbang Grenades
Flashbangs produce an extremely loud blast, typically 170 to 180 decibels, combined with a blinding flash. For reference, 130 decibels is the pain threshold for most people. Tactical teams use them during high-risk entries to create a brief window for securing a room.
The injury risks go beyond the intended disorientation. Flashbangs are incendiary devices that generate intense heat on detonation, and severe burns have been documented when they go off at close range or in confined spaces. The acoustic blast alone can cause permanent hearing damage, and a study published in Scientific Research found that the risk compounds with each additional device detonated and with decreasing distance from the blast.
Long Range Acoustic Devices
Long Range Acoustic Devices (LRADs) project a focused beam of sound that can reach distances of over three kilometers. They are marketed primarily as communication tools, but the same devices can emit piercing alarm tones reaching up to 162 decibels, well past the pain threshold, intended to compel dispersal.
In Edrei v. Bratton, a federal appeals court examined injuries suffered by protesters and journalists exposed to an LRAD during a 2014 demonstration. Plaintiffs reported severe ear pain, prolonged migraines, vertigo, and persistent ringing. One plaintiff’s doctor found the sound pressure had physically displaced a bone in his ear, damaging a nerve. The Second Circuit held that purposefully using an LRAD in a manner capable of causing serious injury against non-violent protesters violates constitutional protections.
The Legal Standard for Police Use of Force
Every use of force by police, including less lethal weapons, is governed by the Fourth Amendment’s “objective reasonableness” standard established by the Supreme Court in Graham v. Connor. The test isn’t whether the officer made the best possible decision, but whether a reasonable officer facing the same circumstances would have acted similarly. Courts are not supposed to judge with hindsight.
Graham turns on three factors: the severity of the crime at issue, whether the subject poses an immediate threat to officers or bystanders, and whether the subject is actively resisting or trying to flee. No single factor is decisive; courts weigh them together against the level of force used. A TASER deployed against someone passively sitting on the ground during a traffic stop looks very different under this framework than one used against someone lunging at an officer with a knife.
Suing After an Injury from a Less Lethal Weapon
If a less lethal weapon injures you and the force was excessive, federal law provides a path to hold individual officers and their departments accountable. Under 42 U.S.C. § 1983, anyone whose constitutional rights are violated by a government official acting in an official capacity can file a civil lawsuit for damages. You can sue the officer who deployed the weapon, and potentially the department or municipality, if the force used was objectively unreasonable under Graham.
The major obstacle is qualified immunity. Officers are shielded from personal liability unless you can show that the specific conduct violated “clearly established” law, meaning a prior court decision with very similar facts already declared that type of force unconstitutional. This is a high bar. Even when conduct seems obviously excessive, courts frequently grant immunity because no prior case addressed the exact weapon used in the exact circumstances. Many meritorious claims never reach a jury.
When individual lawsuits reveal a broader pattern, the Department of Justice can open a civil investigation under its authority to address systemic police misconduct. These pattern-or-practice investigations examine a department’s policies, training, body-camera footage, complaint records, and officer discipline systems. If investigators find systemic constitutional violations, the DOJ issues a public findings report and negotiates a consent decree, a court-enforceable reform agreement that typically includes an independent monitor. These investigations usually take 12 to 18 months, and the resulting consent decrees can reshape a department’s use-of-force policies for years.
Practical first steps after an injury: get medical care and keep every record of your treatment, photograph your injuries over the days that follow, preserve the clothing you were wearing, write down what happened while it’s fresh, and collect contact information for witnesses and any video they captured. Civil rights claims are often won or lost on contemporaneous evidence, and the statute of limitations for § 1983 claims varies by state, so consulting a civil rights attorney early matters.