PARIS (Reuters) - France will vote against renewing the European license for weedkiller glyphosate, an official at the environment ministry said, adding to uncertainty over the future of widely-used products such as Monsanto’s Roundup in the European Union.

Concerns over glyphosate’s risk to human health have prompted investigations by U.S. congressional committees and delayed a relicensing decision in the EU.

“France will vote against the reauthorization of glyphosate due to the doubts that remain about its dangerousness,” a ministry official said.

The European Commission, the EU executive, has proposed extending approval for glyphosate by 10 years after the European Chemical Agency (ECHA) said in a study in March it should not be classified as a cancer-causing substance.

A vote on whether to renew the license is due on Oct. 4, the French official said. A qualified majority of member states is needed for the renewal to go ahead.

In previous votes, France and Germany have abstained, leading the Commission to extend the license by 18 months at the end of June 2016 to give the ECHA time to study the chemical further.