The substances have been used in tens of thousands of products, including aircraft, cars, textiles, medical gear and wind mills due to their long-term resistance to extreme temperatures and corrosion, but PFAS have also been linked to health risks like cancer, hormonal dysfunction and a weakened immune system as well as environmental damage.

The five countries - Germany, the Netherlands, Denmark, Sweden and non-EU state Norway - which have been collaborating on the proposal said in a joint statement that, if passed, it would become "one of the largest bans on chemical substances ever in Europe".

"A ban on PFAS would reduce quantities of PFAS in the environment over the long term. It would also make products and processes safer for humans," they added.

Companies will be given between 18 months to 12 years to introduce alternatives substances, depending on the application and availability of alternatives, according to the draft proposal.

Makers and users of PFAS, which have formed a lobby subgroup under the European chemical makers' association CEFIC, include BASF, 3M, Bayer, Solvay, Merck KGaA and Synthomer.

"In many cases, no such alternatives currently exist, and in some they possibly never will," the five countries said in their statement, adding that companies now need to start to find substitutes.

The moniker "forever chemicals" stems from their ability to accumulate in water and soils because they do not decompose as a result of an extremely strong bond between carbon and fluorine atoms that characterise them.

It will likely take years before the ban takes effect.

Within the European Chemicals Agency (ECHA), two scientific committees for Risk Assessment (RAC) and for Socio-Economic Analysis (SEAC) will now review whether the proposal conforms with wider EU regulation of chemicals known as REACH, followed by a scientific evaluation and consultation with the industry.

ECHA has said that the two committees may need longer than the usual 12 months to conclude their evaluation. Afterwards, the European Commission and EU member states will decide on potential restrictions.

In other regions, initiatives to restrict PFAS are also underway. U.S. industrial conglomerate 3M Co in December set itself a 2025 deadline to stop producing them.

In November, 3M and DuPont de Nemours Inc were among several companies sued by California's attorney general to recover clean-up costs.

Shareholders have also called for production of the chemicals to stop. Investors managing $8 trillion in assets earlier this year wrote to 54 companies urging them to phase out their use.

In August, the United States government said it will propose designating certain forever chemicals as hazardous substances under the U.S. Superfund programme.

DuPont has said it was limiting the use of PFAS to "essential industrial applications" and working with customers to pursue alternatives.

Between 140,000 and 310,000 tonnes of PFASs were sold in European markets in 2020, and the overall annual health costs from exposure to PFAS in Europe has been estimated to be 52 billion-84 billion euros ($55.72 billion-$90.01 billion), according to the draft.

($1 = 0.9332 euros)

(Reporting by Ludwig Burger; Editing by Susan Fenton)