This is what happens when you get tear-gassed


The use of teargas by Hong Kong police marked a key shift in Hong Kong’s evolving pro-democracy movement -- one from peaceful rallies to hostile protests.

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Hong Kong police have used teargas to stop protesters from entering the airport, to remove crowds in the street, and to stop demonstrators from throwing molotov cocktails. 

Police forces say they have fired more than 1,000 rounds of tear gas at protesters since June. Now, reports detail how ordinary residents are now bearing the brunt of the effects of the ‘non-violent-weapon’ as police fire canisters in dense residential areas. 

“We didn’t choose the neighborhoods; it’s the violent protesters who chose,” said senior superintendent Kong Wing-cheung at a press conference in August. 

“So we’re forced to use tear gas in residential areas.”

Media reports quote elderly residents who say tear gas is seeping through the poor seals of their windows. Even the Society for the Prevention of Cruelty to Animals in Hong Kong published guidelines on what to do if household pets are exposed to tear gas. 

Meanwhile, protesters are perfecting how they deal with putting out the projectiles, using objects like traffic cones to trap gas.

What is it like for residents and protesters in Hong Kong who are dealing with the frequent use of teargas? Former military officer Justin Dowden explains what teargas is and what happens when you’re exposed to the chemical.


I vividly remember the sensation of being exposed to teargas. 

There is an overpowering chemical burning sensation that moves to the back of the throat, making it difficult to breath. My eyes involuntarily closed as my mouth, nose and eyes produced more mucus I thought humanly possible.

It took me at least half an hour to ‘decontaminate’, or at least gather my senses and feel in control of my breathing.

I have also seen others get tear-gassed. They start hyperventilating and fall to the ground in a spluttering mess, mucus streaming from the nose, mouth and eyes. It’s not a pleasant sight to behold, but it’s the intended effect. They’re neutralised. 

What is teargas?

Teargas is the common name for o-Chlorobenzylidene Malononitrile or 2-chlorobenzylidene malononitrile (CS). It is commonly used by the military and  by civilian law enforcement as a riot control agent. 

It is categorised by many countries as a ‘non-lethal’ weapon, along with capsicum spray, tasers, and impact weapons such as bean bag rounds.

What happens when you get tear-gassed?

Teargas is a potent sensory irritant that becomes attached to moist mucous membranes and moist skin.

The most common reactions are excessive eye watering, eye twitching, coughing, increased mucus secretion, severe headaches, dizziness, tightness of the chest, difficulty breathing, skin reactions, and excessive salivation are the most common reactions.

The onset of symptoms occurs within 20 to 60 seconds. If the exposed individual is placed in fresh air these symptoms generally stop in 10 to 30 minutes.

Hong Kong protesters react to teargas.
Hong Kong protesters react to teargas.

What are the dangers?

I have seen little evidence of long term damage by exposure to teargas but there is a significant secondary risk. The impact on your senses means you are unable to focus on your surroundings. 

I have seen people injured from not being able to see or hear police horses, riot officers, vehicles that have struck them while they were fleeing or simply standing in the open after being exposed to CS.

Riot police officers fire teargas during clashes with protestors in the Wong Tai Sin District district of Hong Kong, on Monday, Aug. 5, 2019. A top Chinese official overseeing Hong Kong affairs said on Wednesday that the city was experiencing its worst cr
Riot police officers fire teargas during clashes with protestors in the Wong Tai Sin District district of Hong Kong, on Monday, Aug. 5, 2019.

What should you do if you’re tear-gassed?

After someone is exposed to teargas, find a sheltered area. Get some running water on the face and expose them to a dry breeze. Then, all you can do is let time take its course until the effects pass.

The gas will impregnate clothing, so you will need to remove, bag and wash several times, or through them in the bin. Any exposed skin should be washed with soap and water. Shower first in cold water, then warm water. Do not bathe as the crystals which form the gas may relocate to more sensitive regions of the body.

Do not rub your eyes or face, or this will reactivate any remaining crystals, or even just push them further onto the pores of the skin and delay decontamination.

Justin Bowden runs a security risk and crisis company that provides specialist training and operational support to people working in high risk environments.