Flashbangs, Tear Gas, and Rubber Bullets: How Extensive Are These Injuries?

Robert D. Glatter, MD; Rohini J. Haar, MD, MPH; Joseph V. Sakran, MD, MPH, MPA


July 17, 2020

This transcript has been edited for clarity.

Robert D. Glatter, MD: Hi. I am Dr Robert Glatter, advisor for Medscape Emergency Medicine. Today's focus will be on the physical effects of crowd-control agents such as tear gas, pepper spray, and rubber bullets.

Here to join us for a discussion on this topic is Dr Rohini Haar, an emergency medicine physician and research fellow in human rights at the UC Berkeley School of Law, along with Dr Joseph Sakran, a trauma surgeon and director of emergency general surgery at Johns Hopkins. Welcome to both of you.

Dr Haar, would you describe the main physical effects and injuries caused by these agents that we often refer to as lacrimates (eg, tear gas and pepper spray)?

Rohini J. Haar, MD, MPH: The term "tear gas" is a common or general parlance for a wide variety of different agents. They contain more than just one chemical compound. The typical ones used are CS, which has been around for over 100 years, as well as some of its successors (CS1, CS2, CR), which have different levels of potency and a longer shelf life. There is CN ─ an agent used in mace cans ─ and synthetic or natural pepper, which is highly concentrated and weaponized.

The known symptoms are pain to the skin, a sense of burning, tearing in the eye, eyelid spasms (eg, blepharospasm), as well as sensations of pain in the lungs and difficulty breathing, coughing, and respiratory distress.

The vast majority of people exposed to tear gas experience a transient and self-limiting but incredibly severe pain and incapacitation. When it's being misused, people will suffer more significant injury.

Glatter: Getting children to fresh air and up into higher levels off the ground is important.

Haar: Children are closer to the ground, and they have more delicate skin and alveoli. Even at lower levels of exposure, they can suffer a more significant injury. There have been a few case studies indicating that as well.

Glatter: Moving on to the topic of rubber bullets and kinetic impact projectile (KIP) injuries, the research you published in 2017 in BMJ is quite eye-opening. The findings demonstrate that 15% of injuries from the rubber projectiles result in permanent disability and 3% result in death. In my mind, the public is clearly unaware of this. Would you comment on that?

Haar: Let me just qualify that. This was a systematic review of published literature between 1990 and 2015. The vast majority of people who were exposed to crowd-control weapons did not present to the healthcare system. In those who did go to a health clinic or a hospital, the doctors and healthcare workers didn't document their injuries or write papers about them.

The 2000 people we saw in the KIP study were just the few that someone had written a paper about. In those individuals (who sought healthcare for their injuries), we observed very high levels of death and permanent disability.

Those percentages are probably not accurate to the number of people who are exposed in real life. The range and types of injuries that we saw in that review are what we can expect from all different kinds of impact projectiles, even now.

Glatter: Dr Sakran, can you comment on the injury patterns associated with KIPs?

Joseph V. Sakran, MD, MPH, MPA: When we talk about rubber bullets, it's important to clarify a few things. First of all, this category includes projectiles that are made out of all sorts of material, whether it's foam, plastic, or wood, and some even have metal within them.

Historically, the British colonial forces were the first to use special ammunition for crowd control. At that time, they were actually using teak, which is a tropical hardwood. They were not devised to be shot at people but rather at the ground to then deflect up and hit them in the knee — hence the term "knee knockers."

What we commonly referred to as a rubber bullet is what was known as the anti-riot baton round that's essentially made of rubber with a plastic or metal casing. They ended up using the term "rubber bullet" because it was actually meant to persuade the public that these are harmless.

Whether they are lethal or can cause debilitating injury depends on a variety of factors, including distance (ie, whether they are shot from a short or long range) and the location where the person is shot. We have seen folks with serious injuries — soft tissue injury, eye injury and blindness, broken bones, internal bleeding — and, in some circumstances, a fatal injury.

It's hard to say that these injuries are benign. Rubber bullets were introduced with the idea to reduce injuries and casualties caused by conventional firearms. But with this in mind, that these bullets are considered nonlethal, it really depends on the circumstance.

Glatter: Just moving back to tear gas canisters for a second, we've seen significant injuries and even deaths from those. Rohini, would you want to jump in on this?

Haar: In our studies, the tear gas canisters have been one of the biggest causes of significant disability and death. Those canisters are supposed to be fired at the outskirts of a crowd or, at the very least, not directly targeted at individuals. When the canisters actually hit people, especially in the head or the face, that's when you see pretty dramatic injuries such as skull and orbital fractures.

Glatter: The loss of vision or losing an eye is something that's played out all over the media. We've since seen so many images of this.

Haar: Vision loss and globe rupture have occurred with a variety of different impact projectiles or rubber bullets. If you talk to police officers, they are supposed to fire at the largest body mass, which is the chest or the trunk. Because the bullets are so hard to aim and target, it's no surprise that many of them accidentally hit the eyes.

Glatter: Another crowd-control device used is a stun grenade or a flashbang. Joe, can you comment on some serious effects from this device?

Sakran: The flashbang or the stun grenade was designed to temporarily disorient the senses without really killing anyone. It creates a really bright light (the flash piece) and then a very loud noise (the bang). The British Army's Special Air Service developed it in the '70s.

When a flashbang detonates, it ignites a magnesium-based charge that releases a burst of light around 7 million candela. What does that mean exactly? If you have a common candle, it emits light of about 1 candela of intensity. A 25-watt compact fluorescent light bulb emits about 135 candela.

The bright light from these flashbang grenades causes an effect called flash blindness. That's essentially due to the overwhelming overload of the light receptors in the eye that causes significant after-image. The good thing is that these effects are temporary and reversible. The intense light can cause pain, but usually it doesn't cause permanent damage.

The other piece of the device affects the ears by the noise that it creates. The noise is louder than 170 decibels when the ammonium nitrate is detonated. Just to compare, 170 decibels is much louder than a jet engine, which is just over 140 decibels. The loud noise can cause temporary deafness and tinnitus. It can also interrupt the inner ear fluid, which then can cause a loss of balance. Typically, this is reversible. However, at close range, the intensity of the sound of the flashbang could be loud enough to cause permanent hearing damage.

Haar: I'll also add that there are at least 50 documented cases of deaths from flashbangs, primarily when they're fired in enclosed spaces or inside someone's home. There is a case of the police accidentally firing one into a child's crib. These canisters are combustible. Their explosive energy can also cause burns, other significant injuries, and death.

Glatter: This all begs the question about de-escalation prior to the use of these agents. The threshold to use a crowd-control agent on the level of a stun grenade or some projectile is an ethical question that we can all debate. Dr Haar, what are your thoughts on alternative ways to control the crowd?

Haar: I'll start by saying that the vast majority of people, even if a protest turns violent, are peaceful. There are three primary principles that we think about when we even decide to use weapons or just disperse the crowd.

One is necessity. Is it necessary to use the weapon? Have other options been tried? Weapons should always be a last resort. The doctrines say there needs to be open dialogue between police and protest organizers before a protest and ideally during a protest. Usual police tactics (like arresting violent people) could be tried way before the use of weapons.

Two is the principle of proportionality. If someone throws an apple, you really can't justify the use of a high number of crowd-control weapons because of that kind of violence.

Three is use and misuse. The use needs to be legal. These weapons have very specific guidelines for use based on the distance of firing: How many should be fired, in what setting, and what kind of avenues of egress should protesters have if you do fire these weapons. The usage guidelines need to be followed.

Those would be the very first, fundamental steps in developing guidelines on how protests should be policed.

Glatter: There's no requirement that police departments report the use of these agents. Is that correct?

Haar: Correct. Police departments have to report and file incident reports when live ammunition and conventional firearms are used for crowd control. Tasers and pepper spray (items that are less lethal and used during policing) are typically not reported. There are no requirements to report those.

Sakran: From a technological perspective, we have a hard time figuring out how to develop these nonlethal weapons in a way that allows them to address the problem they were initially developed to address.

Historically, when you look back, we know that the whole point of these weapons was to create enough pain to prevent rioters from behaving in certain ways. How do you do that with a minimal impact from injury and death of people who are protesting? It's a complex problem that we've had a hard time figuring out.

Glatter: This has been quite informative. Thank you both for taking the time to join us today.

Robert D. Glatter, MD, is an attending physician at Lenox Hill Hospital in New York City and assistant professor of emergency medicine at Zucker School of Medicine at Hofstra/Northwell in Hempstead, New York. He is an editorial advisor and hosts the Hot Topics in EM series on Medscape. He is also a medical contributor for Forbes.

Rohini J. Haar, MD, MPH, is an emergency physician at Kaiser Medical Center in Oakland, California, an adjunct professor at the University of California Berkeley School of Public Health, and a research fellow at the Human Rights Center at UC Berkeley's School of Law in Berkeley, California. Her work focuses on the protection of human rights in times of complex humanitarian crisis and conflict. She is particularly interested in the protection of health workers and health services. Haar also serves on the board of the San Francisco Bay Area Chapter of Physicians for Social Responsibility.

Joseph V. Sakran, MD, MPH, MPA, is a director of emergency general surgery and assistant professor of surgery at Johns Hopkins University in Baltimore, Maryland. Sakran's interest in medicine stems partly from having nearly lost his life after a gunshot wound to the throat during his senior year of high school, and he has subsequently dedicated his life to making a social impact to curb gun deaths.

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