following several mysterious deaths linked to vaping.

The Centers for Disease Control also said there are 450 cases of a lung illness in more

than 30 states tied to vaping.

There are more questions now than answers.

And William Brangham is back now with more on this mystery.

That's right, Judy.

Health officials say they're still searching for the definitive cause behind these growing

number of lung illnesses.

The Centers for Disease Control and others say they do believe some chemical exposure

is associated with the sickness.

At least four deaths have been linked to vaping, and a fifth is under investigation.

Allison Aubrey of National Public Radio is covering this, and she joins me now.

Hi there.

Welcome.

Hi.

Thank you.

So what is the latest that the investigators are saying?

Sure.

Well, today, they basically came out and said, we still do not know what is causing these

illnesses.

It's very frustrating for them, but they do know a lot more about who has gotten sick.

So, let me paint a picture here.

We are talking young men, average age 19, more than 80 percent of the cases in Illinois

and Wisconsin men.

So these are people who are vaping THC and nicotine, sometimes combinations.

So, a marijuana vape pen and a nicotine vape pen?

Well, putting THC into the vape, right, so vaping THC or other cannabinoids,

CBD, sometimes vaping nicotine and cannabis, so all kinds of mix and match.

It's very, very difficult to hone in on one thing.

And so far, they say they don't see one substance that is linked to all of the illnesses.

So, I'm curious, because New York state officials seemed to indicate

that some Vitamin E substance might be implicated.

Right.

Federal investigators are not echoing that?

Well, they're looking into that as well.

They're looking at a whole range of compounds.

In New York, they say it is a focus.

They found a lot of concentrated Vitamin E in THC vaping cartridges.

And, basically, they're saying, these are not cartridges coming from medical dispensaries

in New York.

These are black market products, stuff that people are buying off the street.

Who knows what's in them, but very high concentrations of Vitamin E. And some people may think, whoa,

Vitamin E, it's a vitamin.

Well, it's fine to take as a dietary supplement or as a lotion.

Not fine to inhale.

Ingested at high levels, when it makes it right into the lung, can cause damage.

So possibly five suspected deaths here, but lots of -- lots of -- hundreds

of illnesses.

How do these illnesses present?

And what do they look like?

Sure.

Typically, what they're seeing is that people feel a little bit sick, and then progressively

have shortness of breath, chest pain.

By day six or seven, they have presented to an emergency room.

And from there, it can get worse.

Oftentimes, they're being intubated, or they need help breathing.

Some have ended up in the ICU.

And they don't know what kind of long-term damage might be done to the lungs.

They just don't know.

You touched on this before, that there are commercial vaping products,

like Juul and Blu, that are e-cigarettes you can buy.

Right.

And then in states where marijuana is legal, you can buy THC vaping

pens.

Sure.

But then, as you're saying, there's also this big black market of these

sort of home brew kits.

Do regulators know whether it's the black market products or the commercial products?

Or they don't know?

They really don't know.

They really -- they're looking at a range of things here.

The people who've spoken up -- and keep in mind, these are 19-year-old young men that

they're asking, hey, you have just gotten really, really sick.

What were you putting in your vape cartridge?

It's hard to get all of the answers.

In about 120 instances, these people who've been sick have actually handed over what's

left of the vaping cartridge.

And that's how investigators are analyzing this.

And they're finding that people have used 12 or 13 different kinds of THC products,

12 or 13 different kinds of nicotine products.

So it's really, really complex and difficult to figure out, is there one substance or combination

of substances that's leading to all these illnesses?

So the CDC says now, until we get to the bottom of this, just don't smoke

e-cigarettes.

You know what?

They are recommending that people stay away from e-cigarettes.

They're saying, if you have been using them to stay off cigarettes, turn to something

else.

Until they know what's going on, until this investigation points to a substance or a product,

they're recommending that people not vape.

Allison Aubrey of NPR, thank you so much.

Thank you.