What is a common name for the substance which irritates lachrymal glands ?

Lacrimal gland, located under the upper eyelid at the outer cornea of the eye, is responsible for tearing during emotional stimulation or following corneal irritation by a foreign body or chemical substance. Tear gas, also called lacrimator, refers to any of a group of substances that irritate the mucous membranes of the eyes, causing a stinging sensation and tears. It produces severe lacrimation by irritating the conjunctivae.