Most sheep dips contain organophosphorus pesticides which are designed to protect sheep from infestations of scab and blowfly. Under real working conditions, farmers and their workers are not protected from hazardous exposure because fumes are inhaled and the recommended protective clothing (rubber gloves, boots and apron) is ineffective. It is argued that only a full "Nasa-style" space suit with respirator could offer adequate protection.
More than 500 British farmers and farm workers claim they have been disabled by blurred vision, muscle weakness, severe headaches, total lethargy and other serious disorders which they believe are caused by the dips. The UK government compelled farmer to dip sheep between 1976 and 1992. Farmers could have chosen to use a safer dip based on a pyrethroid insecticide but it cost twice as much, supplies have been limited, it is not as effective, and the Government denied that organophosphate dips were unsafe to use. The government decision to end compulsory dippings in 1992 is seen as an attempt to avoid legal liability. An outright ban on organophosphate sheep dips in unlikely because it would strengthen farmers claims for compensation and threaten the bigger and more lucrative market for organophosphates as crop pesticides.