Two thirds of EU states have requested to be allowed to ban the growing of genetically modified crops in their countries, choosing the “opt-out” clause of a European Commission rule that allows members to override EU-wide GMO approvals.

Nineteen European Union member states have requested opt-outs from the acculturation of genetically-modified crops for all or part of their territory, the European Commission announced.

GMO-free zone: Germany tells EU it bans genetically modified crops cultivation http://t.co/1agML3YReYpic.twitter.com/3p5Ln69rWc — RT America (@RT_America) October 1, 2015

The Commission rule, passed in March, allowed its 28-member states to abstain from growing GMO crops, even if the specific GMO strain had already been authorized to be grown within the union. Even though GMOs branded as safe by the European Food Safety Authority (EFSA) are allowed for use and cultivation in the EU, the states were given the October 3 deadline to decide on an “opt-out” option.

READ MORE: EU Commission proposes GM opt-out for member states

According to an emailed statement seen by Reuters, the Commission spokesman Enrico Brivio said that 19 countries have said no to Monsanto’s GM maize MON 810. So far it is the only GMO crop commercially cultivated in the EU which is grown in Spain and Portugal.

Belgium and the UK asked for the opt-out mechanism to be applied to only part of their territories, while Germany requested a partial opt-out, hoping to pursue more GMO research.

UPDATE: With Luxembourg, at least 16 EU countries & 4 regions now say NO to #GMOhttp://t.co/C98Hb2traMpic.twitter.com/1EeO3uGtgS — Greenpeace EU (@GreenpeaceEU) October 2, 2015

The full opt-out requests were made by Austria, Bulgaria, Croatia, Cyprus, Denmark, France, Greece, Hungary, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Poland, and Slovenia.

READ MORE: No to GMO: Scotland to outlaw growing of GM crops

The opt-out states de facto are requesting that biotechnology companies exclude their territories from GMO seed sales. Brivio says that requests are being communicated to the companies, which have a month to reply.

The decision would affect major GMO producers, including Monsanto, DuPont Pioneer and Dow Chemical – all developers of herbicide-resistant maize – who have already submitted applications for the cultivation of genetically modified plants to the EC.

The potential use of GMO in Europe has been a widely-debated subject, with environmentalists claiming that it would damage biodiversity.

Ahead of the deadline, Greenpeace said that the growing EU-wide condemnation of GMO products lies in the distrust of EU assessments.

“They don’t trust EU safety assessments and are rightly taking action to protect their agriculture and food,” environmental activist group member Franziska Achterberg said.

Monsanto, whose Roundup herbicide packed with glyphosate was labeled by the World Health Organization’s as a “possible carcinogen,” has led a campaign against the environmentalists ahead of the deadline, claiming that the ban “contradicts and undermines the scientific consensus on the safety of MON810.”