In this week’s protests against police brutality, police in many cities chose to escalate violence. One tool they commonly use is a chemical weapon known colloquially as tear gas. Here’s what to do if you encounter tear gas at a protest. (First step: flush your eyes with water.)
Tear gas is banned during warfare, according to the Chemical Weapons Convention of 1993, but it is legal for police to use on civilians. The intended use, police departments say, is to detonate canisters that spew tear gas at ground level at the edges of a crowd, causing people to run away from the gas, dispersing the crowd.
CS gas is the type that’s usually used when people talk about “tear gas.” It’s actually a solid powder, sent into the air by a reaction with heat and a solvent inside that little canister. (If you’re considering touching or kicking the canister, remember that it’s going to be hot.)
Tear gas begins to cause extreme pain, eye watering, and coughing within 20 to 60 seconds. Once you get away from the gas, symptoms are supposed to subside within 10 to 30 minutes, or an hour at most.
The chemical in tear gas (2-chlorobenzalmalononitrile) is an irritant that targets your body’s pain receptors after reacting with moisture.
That moisture could be the tears in your eyes, saliva in your mouth, mucus in your nose, or sweat on your skin. Your body reacts by producing excessive amounts of tears or mucus, which can make it hard to see or to breathe. The pain and confusion of the experience can be “psychologically terrifying,” according to an expert who spoke to USA Today.
Although the symptoms are meant to be temporary, the gas can cause irritation, burns, and other serious complications in some people. Children are especially at risk, in part because their lungs are smaller and because the gas tends to be more concentrated lower to the ground. People who are elderly and who have health conditions like asthma are also particularly vulnerable. The gas is also more dangerous when it’s used indoors.
Popular Science has an excellent, complete guide to preparing for tear gas and reacting in the moment to protect yourself and to help others. I’d recommend reading it if you think you may end up in a situation where you could be exposed.
The most important thing is this: get away from the gas and flush your eyes with fresh water. Milk may work, but there’s no evidence that it’s better than water. It can also get pretty gross after an afternoon of summer protesting. A solution of water and baking soda may help to inactivate the chemical, but the solution is also likely to contain tiny bits of powder that can scratch or further irritate your eyes. The US Army and the manufacturers of CS gas both recommend flushing eyes with water or saline. (Saline stings less, but both are effective.)
If you think you might encounter tear gas, bring your water in a squirt bottle. Keith Ng, a journalist who has been tear gassed in protests in Hong Kong, recommends carrying saline (or tap water, if you don’t have saline) in a squirt bottle with a small, pointy tip:
Goggles, masks, and full-coverage clothing will help keep tear gas from contacting your body in the first place, but particles of the chemicals can get in, on, and potentially work their way under your protective layers—so be aware of that.
After being exposed to tear gas, remember that particles are likely still on your clothes, belongings, and hair. Carefully remove and wash your clothing, and take a shower to get the rest of the chemical particles off you.