Dimethoate, an insecticide widely used to protect crops such as cherries, could be harmful to humans, the European Food Safety Authority (EFSA), which advises EU policymakers, said on Tuesday.
The report follows a request from France, which is calling for a Europe-wide ban of the substance made by companies including Germany's BASF and Cheminova, part of FMC. Neither firm had immediate comment.
The substance is found in products used on a range of fruit and vegetables, but France raised particular concerns about cherries for which it is used to combat fruit fly.
According to EFSA, there is a lack of information, but it said it could not exclude "a potential long-term consumer health risk resulting from residues".
It cited concerns about toxicity for human health and some U.S. scientific research has found a cancer risk.
France in February banned on its soil a dimethoate-based pesticide used to treat cherries, prompting an outcry from French farmers who say there is no viable alternative.
In a statement on Monday, French Agriculture Minister Stephane Le Foll called for emergency EU-wide measures to prevent the use of products containing dimethoate and the marketing of cherries grown using them.
A European Commission spokesman said the Commission would analyze the report and it would be debated at a closed-door meeting of experts representing the 28 EU member states on Friday.
