Sheep dip

Sheep dip is a liquid formulation of insecticide and fungicide which shepherds and farmers use to protect their sheep from infestation against external parasites such as itch mite (Psoroptes ovis), blow-fly, ticks, and lice.

The world's first sheep dip was invented and produced by George Wilson of Coldstream, Scotland in 1830. That dip was based on arsenic powder and was exported by package steamer from nearby Berwick-upon-Tweed. One of the most successful brands of dip to be brought to market was Cooper's Dip, developed in 1852 by the veterinary surgeon and industrialist William Cooper of Berkhamsted, England.

Sheep dip is available as wettable powders, pastes, solutions, or suspensions which are used to prepare diluted solutions or suspensions. The term is used both for the formulation itself, and the trough in which the sheep is completely immersed.

There are two broad classes of sheep dip: organophosphorus compounds, from which chemical warfare agents were later developed, and synthetic pyrethroids. Organophosphorous compounds are very toxic to humans, as they travel easily through the skin. When traveling over water, containers of sheep dip are subject to United Nations regulations which state that they must remain legible after immersion in water.

...
Wikipedia