EU regulators will not accelerate a decision on whether to restrict use of the world’s most widely used weed killer, even though it has been linked to cancer by the World Health Organization (WHO), officials said on Tuesday.

The International Agency for Research on Cancer (IARC), part of the WHO, said in March that glyphosate was “probably carcinogenic to humans”.

Glyphosate is the active ingredient in Roundup, made by Monsanto, the world’s biggest seed company.

In response to the IARC findings, the U.S. Environment Protection Agency said it may start testing food products for residues.

Campaign group Greenpeace is among those demanding an EU response.

It wrote to Health Commissioner Vytenis Andriukaitis urging him to take account of the IARC decision in an ongoing review of the safety of glyphosate and, as an interim measure, to suspend its use in cases where the exposure risk is particularly high.

His reply, dated May 6, seen by Reuters, said it had not been considered necessary “to consider a precautionary action”.

The current approval period for glyphosate ends on Dec. 31 and the Commission is deciding whether to extend it.

“No decision will be taken until all the steps of the evaluation process regarding a possible renewal, have been completed,” said an EU official, who asked not to be named.

“Relevant scientific elements available will be taken into consideration.”

Some businesses and authorities are already moving to limit glyphosate use.

The German Rewe retail group announced it would cease stocking glyphosate-containing products by the end of September, while German regional ministers have called for a ban on glyphosate use by amateur gardeners, as well as a suspension in municipal parks and playgrounds.

At national level, however, the German government said it would have to wait for the Commission’s EU-wide reassessment.

“Waiting for all scientists, including those on the pesticide industry’s payroll, to agree 100 percent would be reckless,” Franziska Achterberg, Greenpeace EU food policy director, said.

“The Commission must take precautionary action and suspend the use of glyphosate where people are most exposed, either directly or through residues in our food.”

Campaign group Avaaz launched a petition last month calling for a temporary suspension while regulators assessed the IARC findings.

It has been signed by nearly 1.4 million people, including more than 850,000 from the European Union.

Monsanto was not available for comment, although its website includes a statement saying it disagreed with the IARC classification for glyphosate.