The process for evaluating new pesticides must be changed as new technology and safety evaluation procedures are developed. There is an ongoing process to reevaluate the safety of pesticides that were registered before November 1, 1984. More than 1,150 active ingredients have been identified for reregistration. Pesticide manufacturers must evaluate the costs of reregistration versus the potential for sales. Many products presently considered safe will not be reregistered, because the market share is small and the cost of reregistration is great.
Some pesticide residues do occur in foods consumed.
EPA has evaluated the risks of consumption of these residues and concluded that, based on prolonged exposure to the expected doses, no harm will result from consumption. Some individuals insist no pesticide residues should be allowed in foods. This appears to be based primarily on fear of carcinogenicity of these compounds, a fear refuted by many. They cite evidence that frequent damage to DNA by chemicals causing mutations may cause cancer. The assumptions that all synthetic chemical residues in food are dangerous, and all natural substances are not dangerous, have been reiterated by others.