Long­term OP health effects
- the saga continues

Concern is mounting about organophosphate sheep dips. In the last few months, further evidence has come to light which supports fears about the adverse health effects of exposure to these chemicals. David Buffin of the Pesticides Trust [now PAN UK] argues that the products are not safe for some of the 100,000 sheep farmers in the UK.

Results of an epidemiological study on farmers by the Institute of Occupational Medicine show that chronic exposure to organophosphate (OP)-based sheep dip pesticides appears to be associated with subtle changes in the nervous system(1). OP sheep dips may not be safe for some users.
    Epidemiological research on the chronic effects of OPs is rare, and this important study was commissioned in 1992 after reports that sheep dippers experienced exhaustion, long-term fatigue, memory loss and confusion.
    Seven neuropsychological tests were carried out on 146 sheep farmers who had used OPs. Subjects chosen had not complained of adverse effects of sheep dipping. Comparisons were made with 143 non-exposed quarry workers. Dippers took longer to perform tasks requiring sustained attention and mental processing of information.
    Sheep farmers appeared more susceptible to psychiatric problems, although this may be as a result of social and economic factors inherent in sheep farming. The study could not determine whether the effects on the nervous system are permanent or would improve or deteriorate further over time.
    The report concludes that there is a need to reduce the exposure to OPs. This has proved difficult as the recommended protective equipment is now recognised as not perfect, and working long hours in waterproof clothing and a respirator is impossible.
    The Health and Safety Executive (HSE) has welcomed the research: "OP dips are well known to cause ill health effects if no proper precautions are taken. The question explored by the research is whether they are the cause of long term or chronic effects as it is often claimed." At the launch of this study, HSE officials refused to say if, in light of the new data, OP sheep dips should be banned. "It's now up to the Veterinary Products Committee to make their recommendations to Agriculture ministers", said an HSE official.
    Many environmental groups, such as the South West Environmental Protection Agency (SWEPA), Pesticides Exposure Group of Sufferers, Friends of the Earth, the Soil Association and the Pesticides Trust [now PAN UK] believe OP sheep dips should be phased out. "The results of this research show that, even after many years of use, we still cannot be sure that OP sheep dips are safe for every farmer to use" concluded Peter Beaumont, Director of the Pesticides Trust.
    At an HSE seminar on 25 May to discuss the results, criticisms were made about the control group. Industry considered significant differences between the exposed and control groups that could account for the results.
    Farmers and sufferers contend that the results were biased in the opposite direction. "Many people who were excluded by researchers are more likely to have suffered severe effects from OPs" noted Elizabeth Sigmund of SWEPA. Dippers with central nervous system disease, suffering vision impairment, seizures, alcohol or drug addiction, or who take anti-depressants, were excluded. SWEPA consider severe OP sufferers may predominate in these groups.
    There is no satisfactory evidence indicating whether protective clothing is suitable or adequate. HSE believes that licensed OP products are safe provided they are used according to label directions and that protective clothing as recommended by manufacturers is properly fitted, worn and maintained. This may be the case for the majority of users, but a small percentage of individuals become sensitive to OPs. At present no one can guarantee their safety, and the questions arise of what is the level of acceptable risk, and who defines that risk as acceptable.
    On 2 June a conference, run jointly by the British Medical Association (BMA) and the National Farmers Union (NFU), for farmers, medical practitioners and policy makers, addressed the problem of OP sheep dips and health. The two organisations established much common ground and a common purpose. They will hold a series of meetings aimed at developing better links between farmers and doctors (2).

Agriculture committee dips into veterinary products
The House of Commons Agriculture Select Committee is investigating the Veterinary Medicines Directorate (VMD), the agency which licenses sheep dips. Dr Mike Porter, VMD chief executive, has appeared at an oral session. One concern raised is a possible conflict of interest in the role of Dr. Kevin Woodward, chairman of the appraisal panel for assessing ill-health and also director of product licensing. "I cannot understand why you can't see a conflict of interest, it seems as plain as a pikestaff to me," said Dale Campbell-Savours, MP. Dr Mike Rutter, said Dr Woodward is not responsible for the conclusions of the panel, which are reached by independent experts.
    Jean Corston, MP, questioned Dr Rutter over a 1981 HSE report which linked nerve damage and 'expressive language defects' to OPs. "It is amazing that people were not told about this, especially the NFU, doctors and staff at the HSE," she said.

Delay in OP research
On 1 December 1993 the government set up a panel of experts to look into ill health following OP sheep dip exposure. The panel rejected all 13 proposals (including one from MAFF's laboratories and another from the Institute of Occupational Medicine at Birmingham University. The delay in starting this vital research has been taken up in the House of Lords(3) by the Countess of Mar, an OP victim. "I, and a great many other people who are interested in the subject, are still not convinced that the government is not using delaying tactics." For the government, Earl Howe said he was concerned and disappointed that none of the studies were considered acceptable. "It is highly regrettable" he concluded.

Pesticides Trust [now PAN UK] comment

• This research adds to the body of evidence that sheep dips containing OPs are not safe for some users.
• Safer non-OP methods of control for scab and blowfly strike should be brought forward as a matter of urgency to reduce the risks to farmers, sheep and the environment.
• Hazards must be assessed by an independent expert committee, but users should be involved in deciding the acceptable level of risk.

1. Neuropsychological effects of long-term exposure to OP sheep dips, Richard Stevens and Anne Spurgeon, Lancet, Vol. 345 May 6 1995. Research commissioned by the HSE, carried out by the Insti
tute of Occupational Health University of Birmingham.
2. BMA and NFU, OP Sheep Dips and Human Health, proceedings will be available from Colin Byrne of the NFU.
3. Hansard, cols. 1367-1169, 3 May 1995.

[This article first appeared in Pesticides News No. 28, June 1995, page 3]