Tear Gas | 22 Nov 2019

Why in News

The extensive use of tear gas by the police in Hong Kong's protests and the lack of government-led cleansing and decontamination procedures has generated mounting public concerns about potential short and long-term health effects of tear gas.

Definition: Tear gas, also called lacrimator, is a group of substances that irritates the mucous membrane of the eyes. This causes a stinging sensation and tears. They may also irritate the upper respiratory tract, causing coughing, choking, and general debility (physical weakness).

• The effects of tear gases are temporary and reversible in most cases. Gas masks with activated charcoal filters provide good protection against them.

Background: It was first used in World War I in chemical warfare, but since its effects are short-lasting and rarely disabling, it came into use by law-enforcement agencies as a means of dispersing mobs, disabling rioters, and flushing out armed suspects without the use of deadly force.

Substances Used: The substances most often used as tear gases are synthetic organic halogen compounds. They are not true gases under ordinary conditions but are liquids or solids that can be finely dispersed in the air through the use of sprays, fog generators, or grenades and shells.

• Other compounds used in tear gas include Oleoresin Capsicum (OC, or pepper spray), bromoacetone, benzyl bromide, ethyl bromoacetate, xylyl bromide, and α-bromobenzyl cyanide.

Types: The two most commonly used tear gases are:

• 1-chloroacetophenone (CN)- is widely used in riot control which chiefly affects the eyes, and
• O-chlorobenzylidene malononitrile (CS)- is a stronger irritant that causes burning sensations in the respiratory tract and involuntary closing of the eyes.