Two years after his heart stopped, Mike Watters climbs aboard his lawnmower and pulls on a black, Darth Vader-like mask.

The US special forces veteran fixes the strap around his head then starts to breathe through the air vents.

It is a hot spring afternoon in Gray’s Creek, North Carolina, a bucolic rural neighbourhood where clap-board homes poke through glades of pine trees and wisteria.

Mr Watters turns the key in the ignition of his mower and begins to drive across the grass of his back-yard.

To the naked eye, there would appear no reason for the eerie headwear.

But Gray’s Creek is contaminated ground. The grass, the soil, the water – and the local residents – are suffused with PFAS, or Per- and polyfluoroalkyl substances, a class of chemicals so tough they may never be broken down.

In 100 years’ time – even a thousand – the so-called forever chemicals will remain on Earth, outliving all the suburb’s 10,000 residents.