What to do if you are hit with tear gas: seek high ground, find fresh air, and rinse off with cool water

Police fired tear gas outside the White House late Sunday as anti-racism protestors took to the streets to voice fury at police brutality, and major US cities were put under curfew to suppress rioting.Jose Luis Magana / Getty Images

• Tear gas was invented a century ago, and has long been used as a weapon to control crowds.
• When tear gas gets into the eyes, it can cause temporary blindness, while exposed skin often gets red and feels like its burning.
• Here's a step by step guide for what to do if you are exposed to tear gas during a demonstration, how to safely remove your clothing, and how to clean up.

Police have used tear gas against protesters in cities across the country this week as people seek justice for the deaths of George Floyd, Breonna Taylor, and other black Americans at the hands of police.

Though tear gas was classified as a chemical weapon in 1993 and banned from use in international warfare, officers are still allowed to use it on civilians in the US.

Tear "gas"is actually not a gas at all — it is a solid, white powder that can be aerosolized when mixed with a solvent. When it's mixed with water, sweat, and oils in our skin, it dissolves into a painful, acidic liquid that makes people cough and sneeze. Heat and humidity often make it feel even worse.

The most important thing to do immediately if you're tear-gassed is to move away from the cloud of gas.

"Stop the exposure," Dr. Rohini Haar, an emergency physician and crowd-control weapons expert with Physicians for Human Rights, told Insider.

Here's a step by step guide on what to do next if you're exposed.