The dangers of sheep dip – the essential facts

Recent reports have revealed that since 1951 there have been fears that sheep dip was damaging the health of farmers. We break down the issue into need-to-know facts and figures.

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The sheep dip poisoning scandal has returned to the news after MPs called for an inquiry into whether farmers have been misguided over the use of dangerous chemicals called Organophosphates (OPs), used to protect livestock from parasites. We break down the issue into bite-size facts to help make sense of the headlines.


1. OPs were originally created as a nerve gas and were developed during the Second World War. Source: Wikipedia.

2. In 1951 Lord Zuckerman, who would go on to become the government’s chief scientist, warned of the dangers of allowing farmers to use OPs. Zuckerman raised concerns that farmers could absorb the poison through skin or inhalation. Read the legal notice published by Minister of Agriculture and Fishery regarding the harmful effects of Ops in 1951. Read a report published by Tim Farron, MP, stating that Government knew about the harmful effects of OPs. 

3. Zuckerman called for farmers to be given detailed instructions for the use of OPs and for the substance to be labeled as deadly poison, although neither suggestion would be adopted until the 1980s. 

4. Dipping sheep became compulsory in the late 1970s, and the use of OPs specifically was mandated by the British government until 1992. Read abstract at Small Ruminant Research

5. In 1981 an advice leaflet was produced by the Health and Safety Executive (HSE) that warned against the dangers of using OPs, citing that the chemicals could be absorbed through the skin. A report from the HSE in 1990 showed growing concerns over the use of the chemicals. 

6. UCL’s Dr Sarah MacKenzie Ross reviewed existing scientific evidence in 2013 and found that 13 out of 16 studies showed evidence of neurological problems following long-term, low-level exposure to Ops. Long-term health issues linked to OP poisoning also include multiple sclerosis and memory issues. Source:

7. The number of farmers suffering from ill health following the use of OP sheep dips is estimated at between 500 and several thousand. In 2000 the Guardian reported that 25 children were amongst the sufferers. 

8. In April 2014 MPs called for a ‘Hillsborough-style’ inquiry into the sheep-dip poisoning, with Shadow health secretary Andy Burnham called it a “major scandal”. Source: Agri Wales

9. Farmer’s Weekly reported that in 2015 Tom Rigby, coordinator of the Sheep Dip Sufferer’s Support Group, submitted a Freedom of Information act asking the HSE for documents regarding the abandonment of compulsory dipping but as informed that the documents had been “destroyed in accordance with HSE’s corporate retention policy”. Source: Farmer’s Weekly.


10. In 2015 the trade body representing animal health product manufacturers, NOAH, said “while there is an acute risk from direct contact with concentrated OP dip, low level exposure to correctly diluted sheep dip is not considered to be a chronic health issue.” Source: Farmer’s Weekly.