Thousands of farmers, farm workers and even officials supervising dipping suffered debilitating ill health from using the chemicals under government orders, to protect against sheep scab.
The Government made a partial release of evidence last week to explain why it ended mandatory use of OPs in 1992. These documents showed ministers were advised to end use of the chemical because of its failure to eradicate sheep scab.
However, officials have not yet released the results of blood tests known to have been undertaken in 1991 and 1992 on farmers who had reported illness.
Conservative MP Neil Parish, chairman of the Environment, Food and Rural Affairs select committee, has written to officials and said he would not rule out an inquiry into whether farmers were misled about the reasons for the Government ending compulsory use of the chemical until he had seen this evidence.
Although the blood tests, undertaken at Guy’s and St Thomas Hospital, London, are not mentioned, the documents released last week show ministers were advised ’the risk to farm workers of adverse reactions have caused increasing public concern’.
They were also told there had been 174 incidents of adverse reactions in people following the use of the chemical between January 1991 and April 1992.
MPs suspect the Government knew about the health impacts of using OPs before it decided to end compulsory use in 1992, but were worried about legal action from manufacturers.
The former MP Lord Tyler has said he was told privately by the then Farming Minister John Gummer (now Lord Deben) that he could only say dipping had been ineffective at eradicating sheep scab.
Lord Tyler said: “Mr Gummer confessed privately to me in 1992 that he was advised by lawyers that a fuller explanation of the reasons for the withdrawal of the compulsory dipping order would have resulted in very unwelcome and expensive legal action from the manufacturers. So they claimed it was due simply to lack of proven efficacy.”
Mr Gummer himself has said he always consulted the ’best available science’ during his time as a minister but did not respond to requests to comment about the recent release of documents or the remarks of Lord Tyler.