This is the Guardian. They are found in the blood of people in Oatman, Arizona, and they are found in the blood of people in Fargo, Dakota.

They are found in me. They are found in my kids. They are found in every one of you.

That's actor and environmental campaigner Mark Ruffalo

talking to US politicians about P-FAS, aka Forever Chemicals, so-called because once an environment

is contaminated with them, they stick around for a long, long time, building up and up.

They've been found pretty much everywhere, in the environment, in animals, and even in

our blood.

But a new investigation has revealed the scale of the pollution in the UK and Europe

and discovered high levels of forever chemicals at thousands of sites.

So what are P-FAS? How toxic are they?

And what can we do to protect ourselves to reduce their impact or just to

avoid them completely. From the Guardian I'm Madeline Finley and this is Science Weekly.

Rachel Salvage you're an environmental journalist and founder of Watershed, an investigative organization focusing on water issues, and you've just published an investigation in the Guardian about P-FAS, so-called Forever

Chemicals.

So to start us off, what exactly are P-FAS?

P-FAS, it stands for per and polyfluoral al-cal substances, so I'm quite pleased that we have a

shorthand for it. But it's an umbrella term for a family of thousands of chemicals, so around 10,000, or I've actually seen a study saying that there might be around 12,000 on the market at the moment.

And their prize for their indestructible non-stick properties.

So if something is grease-proof or waterproof,

it's likely that there is a P-FAS doing that job in that product.

It was originally the Teflon chemical,

that's how you had your non-stick pan but you can get it

...