JOHN YANG: There's a class of toxic chemicals so pervasive that they're found in food, soil, water and in the blood of most people in America.

Earlier this month, the EPA proposed the first ever regulatory standard to limit the quantity allowed in drinking water.

Ali Rogin looks at the growing health concerns about these chemicals.

ALI ROGIN: PFAS, sometimes called forever chemicals, repel fire, water, oil and stains and have been used since the 1940s in a wide variety of everyday products.

You can find them in nonstick cookware, fast food wrappers, clothes, and cosmetics.

But these manmade chemicals don't break down easily, and a number of them have been linked to serious health problems.

For more on their impact, we turn to Erin Bell.

She's an environmental epidemiologist at the State University of New York at Albany who studies human exposure to these toxins.

Erin, thank you so much for joining us.

Just how widespread are these chemicals?

ERIN BELL, Environmental Epidemiologist: These chemicals have been detected in the drinking water and soil in every state of the United States, and it is also being detected in many countries across the world.

A number of health concerns are related to exposure to these chemicals.

They include impact on the immune system.

Folks with higher exposures are more likely to have thyroid changes in kidney function as well as higher cholesterol.

We're also concerned about impacts on children with regards to low birth weight and neurodevelopment in those children.

There are a number of other health outcomes where the literature is more mixed.

We sometimes see an association, other times we see less of an association, and we have more work to do.

These would include infertility factors around ulcerative colitis and other autoimmune diseases.

ALI ROGIN: Are these things that people can determine by taking a blood test?

I mean, how does one test to see where their levels are?

ERIN BELL: That's correct.

For each individual, we measure concentrations in their blood, and that is the best way to determine the individual level of exposure for people who have lived in communities or for people in occupations that have these higher exposures.

Unfortunately, there's no consistent guidance or coverage from insurance companies for testing for PFAS in your blood.

If you contact your local health department, they will let you know if there are programs at the state level sponsored through state health departments if they have opportunities for you to get tested.

This is a situation that we're still working on in terms of making sure there's coverage for people to get tested if they wish to know what their levels are.

ALI ROGIN: Now, the EPA, as we mentioned in the introduction, is proposing a new regulation pertaining to PFAS in water.

Can you explain what exactly this proposal would do?

ERIN BELL: There are 12,000 chemicals in the family of PFAS.

The EPA has suggested that for six of these chemicals, there be a standard federal rule that would require that water utilities test for these six chemicals and if they were above a certain level that those chemicals would be monitored for and regulated and companies would be required to reduce their exposure in the water utility.

ALI ROGIN: Now, six out of 12,000 doesn't sound like a lot.

Are we missing something here?

Are these very significant versions of these chemicals?

ERIN BELL: So that's an excellent question and this is one of the challenges we have in the field.

Out of the 12,000 we've obviously studied very few of them.

So these six are particularly concerned because we know the most about them.

We also have detected them in higher levels in drinking water across the country.

However, it is quite literally a drop in the bucket.

It is just a very small number.

There is concern in the scientific community that we will never catch up in terms of understanding what the health effects are for the much larger group of PFAS.

ALI ROGIN: How is it that these companies are able to continue to manufacture products with these dangerous chemicals in them?

ERIN BELL: So historically, when we talk about environmental exposures and removing them from production, we focus on their persistence.

They stay in the environment and in our bodies for a very long time.

The newer versions, they are not as long lasting in the environment.

However, because they are structurally designed to, in essence, do the same thing that made them good for production and for our consumer products, they're still related to some of these adverse health outcomes.

So, they're still being used because we have not regulated them and we still require them in the manufacturing process.

And until those rules and laws change, then that will be allowed to happen.

ALI ROGIN: So my understanding is that this EPA rule, if it is approved, is still going to take a few years before it's fully operational.

What kind of things can people do if they want to begin reducing their exposure now?

ERIN BELL: There are a number of things that people can do and communities can do.

The first is awareness.

Please be sure and keep mindful of what might be going on in your community, especially in the drinking water.

If you are not sure what levels of PFAS are in your drinking water, you can contact your local water utility, your state health department, as well as any university or college researchers that are in the area.

In terms of reduction, we can use filters on our water systems and in our homes.

You also want to be mindful of what you use on an individual basis, again, minimizing fast food wrappers.

The wrappers are lined with these materials, as well as microwave popcorn is another example.

Pots and pans have these linings.

As they become scratched, the PFAS can leach into the food and cause us more exposure.

So again, be mindful of that and as you replace them with things that don't have the nonstick chemicals or have the other types of coatings on them that would potentially have these chemicals.

ALI ROGIN: Erin Bell with SUNY Albany.

Thank you so much for your time.

ERIN BELL: Thank you.