Eleven executives from companies including Japan's Mitsubishi and Luxembourg-based International Chemical Investors (ICIG) were convicted for contaminating nearly 200 square kilometres (77 square miles) of drinking water as well as soil through the Miteni plant in the northeastern city of Trissino.

The court sentenced them to prison terms ranging from two years and eight months to 17 years, in the case of two executives at now-folded Italian firm Miteni.

Four other defendants were acquitted.

PFAS -- or per- and polyfluoroalkyl substances -- are a group of more than 10,000 human-made chemicals that repel heat, water, oil, and stains.

Developed in the 1940s, they are still used in nonstick pans and stain-proof carpets, yet are now linked to hormonal disruption, immune suppression and cancers.

Their ultra-tough carbon-fluorine bonds take millennia to break down in the environment.

The now-shuttered plant produced PFAS from 1968 and was run by three companies until its closure due to bankruptcy in 2018.

It leaked chemical-laced waste into a waterway, polluting a vast area between Vicenza, Verona and Padova, according to prosecutors.

The trial opened in 2021.

Prosecutors had requested cumulative jail terms of 121 years. The court's sentence was even tougher: a total of more than 141 years.

Hundreds of civil plaintiffs joined the trial, including environmental group Greenpeace and local mothers who united after discovering their families had the chemicals in their blood.

Greenpeace Italy representative Chiara Campione called the ruling "historic" in a statement.

The individuals and companies involved were sentenced to pay more than 6.5 million euros ($ 7.6 million) in damages to the Veneto region -- a ruling welcomed by regional leader Luca Zaia.

They will also have to pay 58 million euros in damages to the Italian environment ministry, according to media reports.

In May, a court ruled the death of a worker at the plant who died of cancer in 2014 was caused by prolonged exposure to PFAS.