Specifically, the article states, "When the occurrence of any damage, albeit unpredictable in the current state of scientific knowledge, may seriously and irreversibly harm the environment, public authorities shall, with due respect for the precautionary principle and the areas within their jurisdiction, ensure the implementation of procedures for risk assessment and the adoption of temporary measures commensurate with the risk involved in order to deal with the occurrence of such damage."

In other words, in principle, a temporary ban on the use of the bags could be imposed, while their risks are being investigated.

The MPs backed up their January 8 legislative proposal with a number of arguments, writing that, unlike biodegradable plastics, oxo-degradable plastics fragment and disintegrate into fine particles of plastic, without degrading into water, carbon dioxide and organic matter. Very fine particles pollute the marine environment, they noted, citing a Belgian study, which showed the presence of micro-plastics in mussel shells. The risk is considerable that these particles are therefore also contaminating the food chain. Oxo-degradable plastics furthermore do not qualify as biodegradable under the current standards, they said.

The MPs also pointed out that these plastics formed a "menace" for the budding composting industry in France, and pose a problem for recyclers. Moreover, they wrote, oxo-degradable plastics are mostly manufactured in Asia, which makes it very difficult to check what additives have been used to produce them.

Ultimately, they proposed to ban the use of oxo-degradable plastic bags until it can be proven that they pose no health and environmental risks.

The Oxo-Biodegradable Plastics Association (OPA) has since responded with a furious press release. Lambasting what it sees as "a skillful lobbying attempt to take oxo-biodegradable plastics off the French market and leave the field clear for bio-based plastics which are not competitive with oxo-bio and have very limited usefulness. Lobbyists are trying to do the same in Italy and Spain, and risk making fools of the Deputies in these three countries."

The statement continued:

"It would be surprising if the French Government allowed this proposal to pass into law, because in a civilized country you cannot close down a lawful business on the basis of a mere suspicion - you need to have credible evidence to justify such a serious interference with freedom. Moreover, any such law would contravene Art 18 of the EU Packaging Waste Directive, and even if that article were eventually amended as proposed by the Commission, it would still contravene Article 36 of TFEU (Treaty on the Functioning of the EU)? Their main point seems to be that fragments of plastic might contaminate food and the environment. However, everything will fragment into the environment as it degrades, for example paper, textiles, conventional plastics, and bio-based plastics.  Are they going to ban them all, even if they are not toxic?"

The association went on to counter the arguments of the French MPs, point by point. According to OPA, the Belgian study cited concerns particles of conventional plastics, not oxo-degradable ones. The association also repeated the conclusion of a 2012 report from Roediger laboratories that "plastic products made with oxo-biodegradable technology may be recycled together with conventional oil-based polymers without the need for separation and without any significant detriment to the newly-formed recycled product." 

Interestingly, the very first point made by OPA touched the very heart of the discussion. The association wrote: "A group of members of the French National Assembly have proposed a law to ban oxo-biodegradable plastics - not on the basis that they pose risks to health and the environment, but on the basis that they just might."

Exactly. Remember asbestos, to name one example?

This time around, wouldn't it be nice to know for sure before we wholeheartedly embrace the use of these materials?