OP sheep dips and heart disease - a case history

Sheep dip poisoning came to public attention with media reports of farmers suffering serious ill­health following dipping of sheep with organophosphate (OP) pesticides. The products used are not registered as pesticides but are licensed as veterinary medicines by the Veterinary Medicines Directorate (VMD). Alan Care examines a case history where a heart attack followed OP dip exposure.

Farmers and other users of OPs complain of many symptoms which are often not specific but include headache, nausea, sweating, muscle tremors, anxiety and depression, shading into longer term neurological complaints.
    The current High Court claim of Gary Coomber, a Kent sheep farmer, is an exception. He suffers the specific heart disease myocarditis-caused, it is alleged, by exposure to OP sheep dip. Mr Coomber used a sheep dip containing the active ingredient propetamphos, an OP insecticide, in 1991 and suffered from myocarditis (akin to a heart attack) within about seven days. Prior to the attack he suffered flu-like symptoms. The following year he again used a propetamphos sheep dip and again within seven days suffered another heart attack. After extensive investigations by his GP, Dr Bernhardt, the link between Mr Coomber's heart condition and OP exposure was suspected. He was advised to avoid sheep dips and did so the following year. However, in 1994 whilst walking though a field, he came into contact with another farmer's flock of sheep that had, unknown to him, been dipped. Again within seven days he suffered a heart attack. According to his GP Mr Coomber may well have died.
    Professor William McKenna of St Georges Hospital London believes Mr Coomber's illness was caused by exposure to OPs. Mr Coomber has sued the sheep dip manufacturers and uniquely brought proceedings against both for negligence, contending that the manufacturer was in breach of a duty of care owed to him by failure to warn, and under the Consumer Protection Act 1987, alleging that the product was defective and unsafe within the meaning of the Act. This is the first case of its type where it is alleged that the sheep dip, as a licensed veterinary medicine, was an unsafe product. The manufacturers will defend the action in respect of each count.
   
There were no warnings given by the product manufacturers of the danger of myocarditis following use of sheep dips. However there have been indications of such problems in the medical literature-for example, 'Effects of OPs on the heart' and 'Cardiac effects of anticholinesterase agents' in Ballantyne and Marrs(1). As early as 1966 Dr Limaye drew attention to the heart problems of OPs(2). In the HSE publication (MS 17 December 1980) there is mention of "slowing of the heart with decreased cardiac output." In Israel in 1982 Dr Ludomirsky and his colleagues referred to the problem of ventricular arrhythmias (variable heartbeat) associated with OPs(3). In 1983, Dr Grabowski from Miami (US) reported heart abnormalities observed in rodent studies(4). In 1984, the Indian Medical Journal reported 'Cardiac toxicity in pesticide formulators exposed to OP insecticides'(5). In 1985, an incident involving "seizures and cardiac arrest in a farmhand" was reported(6). In 1979, Dr Fazekas from Hungary reported 56 OP patients with arrhythmias(7).
   
Pesticides cause many different effects. I have dealt with over 300 claims of pesticide and chemical poisoning, most of which have been settled out of court by insurers, though usually with no admission of liability. These are often acute injuries with relatively short lived consequences to health and recovery. Damages are often recovered in the range of £3,000-£5,000. One must exclude the possibility of long term effects before settlement.
   
Sheep dip claims are different. In many such cases farmers have lost everything and will be seeking substantial damages-but long-term effects will have to be proved. Whether the courts will find that OPs are dangerous per se and effectively impose strict liability on the manufacturers of sheep dips will also be an issue in this test case litigation.
   
The role of the Legal Aid Board (LAB) and National Farmers Union (NFU) is crucial in assisting farmers to fund claims to recover damages. So far the NFU has not funded a single claim on behalf of a member despite their own survey confirming a problem nation-wide. Perhaps the NFU's reluctance to throw its weight behind the farmers is because they are caught on the horns of a dilemma. Its membership includes farmers who wish to sue sheep dip manufacturers but also farmers who will be sued by employees.

Who to sue?
Many believe that as the sheep dips are licensed as 'safe', proceedings may lie against the government. My own view is that this is unlikely-the government relies upon the advice of experts. Steps prior to licensing are lengthy. Unless it can be shown that those experts ignored mounting evidence and acted irresponsibly, I doubt they will be blamed with hindsight.
   
The government also relies heavily upon information provided to them by the manufacturers. They have no independent testing facility. It is surely for the manufacturer to inform the government if new knowledge becomes available about the product to prompt warnings, label changes or other action. Campaigners feel that the government's entrenched position is now unacceptable-the government has licensed OPs as 'safe'; has insisted upon their use; and now appears to wash its hands of the problems. The government should, however, now accept responsibility and establish a compensation scheme for those who have been injured.
   
OPs, in the form of chemical warfare agents, were investigated by the Chemical and Biological Defence Establishment (CBDE) at Porton Down. CBDE has been asked to provide details of its work-particularly on human volunteers. The issue of whether OP exposure can cause myocarditis has already been answered by the Royal College of Physicians in their 1991 publication Some aspects of the medical management of casualties of the Gulf War. The 'supplementary advice' relating to a Department of Health document Gulf contingency planning: NHS medical guide, noted: "Nerve agents ... Experience of insecticide poisoning has shown that after apparently successful treatment patients may deteriorate rapidly at any time. Further respiratory failure, insomnia, psychiatric and myocardial problems including arrythmias may occur."
   
How long will the farmers have to wait for the government to heed warnings first given in the Zuckerman report in 1951 and reiterated in the advice of the Royal College of Physicians? Has the government itself taken sufficient action or is it exposed to challenge in the Courts for compensation?

References
1. Ballantyne, TW and Marrs, T, Clinical and Experimental Toxicology of OPs and Carbamates, Butterworth and Heinman, 1992.
2. Limaye, MR, Acute OP compound poisoning: A study of 76 necropses, J Indian MA, 1966, Vol 47.
3. Ludomirsky, et. al. Q-T Prolongation and polymporphus ('Torsade de Pointes' ventricular arrhythmias associated with OP insecticide poisoning, American Journal of Cardiology, 1982, Vol. 47:1654-1658.
4. The electo-cardiogram of foetal and new born rats and dysrythmias induced by toxic exposure, 1983.
5. HN Siyed, SK Gupta, JP Jani and SK Kashyap, Cardiac toxicity in pesticide formulators exposed to OP insecticides, Indian Medical Journal, 1984, Vol. 80:494-498.
6. Grace, TW, Hospital Practice, June 15 1985.
7. Fazekas, & Kiss, Arrythmias in OP poisonings, Acta Cardiologica, 1979.

Alan Care is a lawyer with Leigh Day & Co and is also on the Pesticides Trust [now PAN UK] Board
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[This article first appeared in Pesticides News No. 31,March 1996, page 11]