OP dips could slip through test safety net
By Liz Mason
GOVERNMENT safety tests may be failing to stop sales of organophosphorus sheep dips that cause permanent nerve damage.
The test, known as the hen test because it is carried out on female chickens, has been in use since the late 1950s. But recent research suggests OP chemicals that cause delayed neuropathy may be slipping through this chicken safety net.
Dr Timothy Marrs, senior medical officer at the Department of Health told a NFU/BMA seminar it was the policy of "regulatory bodies" to use the hen test to not allow OPs on the market that cause delayed neuropathy. But two recently published scientific papers questioned whether the hen test excludes these chemicals.
"It is possible that the hen test does not predict quite as well as we think it does," said Dr Marrs. OPs were first discovered in the 1930s by a German scientist and the effects of acute poisoning were investigated in the 1940s. Delayed neuropathy was researched in the 1950s and hens were found to be the most sensitive indicator of this type of nerve damage.
A MAFF spokeswoman later denied that ministry licensing officials use the test. "It doesnt mean anything to us because it is not something we do." She added that MAFF "wouldnt test pesticides on chickens".
But a Department of Health spokesman confirmed that the test, which had been refined since the 1950s, was still being used by the MAFF agencies responsible for licensing OP sheep dips and pesticides. He added that the Veterinary Medicines Directorate takes its lead from the hen test and, therefore, any OPs which were found to test positive were kept from the market.
• Health and safety officials have dismissed claims that new European rules on protective clothing will force a ban on OP sheep dips.
But HSE advice to sheep farmers is "only to use OP dips if you have to".
A HSE statement said a new directive, which comes into force on July 1, requires manufacturers (PPE) to meet "essential safety requirements".
Manufacturers can label clothing that meets this requirement with a CE mark. But existing PPE without the mark can continue to be used, said the HSE provided it is suitable and properly maintained.