Although, this broad definition applies to almost all of the chemicals typically used in laboratories.
Irritants are materials that cause inflammation of the body surface with which they come in contact.
The inflammation results from concentrations far below those needed to cause corrosion. A primary irritant exerts no systemic toxic action, either because the products formed on the tissue of the respiratory tract are non-toxic or because the irritant action is more severe than a systemic toxic action. A secondary irritant's effect on mucous membranes is overshadowed by a systemic effect resulting from absorption. Simple Asphyxiants deprive the tissue of oxygen. Simple asphyxiants are inert gases that displace oxygen.