that mixed really well with the clay they used to make pots.

This stone was so strong, and yet flexible, that they could use it to make their pots

thinner and bigger than ever. Plus, it was surprisingly resistant to heat, so the pots

could hold things like hot metal.

It seemed like a miracle stone, and eventually, the ancient Greeks, Romans, and Egyptians

all started using it, too.

That rock was what we now call asbestos, and eventually, we found out that it was too good

to be true and stopped using it as much.

But that took a while.

The word asbestos actually refers to six different minerals that all have the same habit, or

way that their crystals grow.

They’re called asbestiform, which just means that they grow in long, thin, flexible fibers.

That flexibility, plus their strength and resistance to damage by heat and harsh chemicals,

made these minerals incredibly useful in industry. The problem is, inhaling asbestos fibers can

be dangerous.

Because to your lungs, those flexible fibers are more like sharp little shards.

You can probably imagine what happens if you breathe them in: they get stuck in the mucus

lining of your lungs, which can make it difficult to breathe.

Inhale too many shards over time, and they can cause diseases like asbestosis, or scarring

of the lungs, and mesothelioma, a type of lung cancer.

The forms of asbestos with the highest health risks are a part of a group of rocks called

amphiboles, and what makes them cause more health issues than others comes down to four

of their chemical and structural properties.

First, amphibole fibers are smaller, so they can travel deeper into the lungs.

They’re also sharper, so they can pierce your lungs more easily, causing inflammation

or creating scar tissue.

Plus, they’re hydrophobic, or water-avoiding, which can keep them from dissolving in mucus

-- if they dissolved, they could be coughed up and get out of your system.

Finally, they contain iron, which can react with oxygen in your lungs and damage the DNA

in your lung cells.

The damaged DNA can then make the cells to divide too quickly, leading to a tumor. So

they may be more carcinogenic, or cancer forming, as well.

So, how did asbestos go from being the miracle-rock of ancient potters to the scourge of modern

industry?

Even as far back as the Roman Empire, some 2,000 years ago, historians wrote about slaves

getting what they called a “sickness of the lungs” after working in asbestos mines.

And when the first commercial asbestos mines opened in Quebec in 1879, asbestos-related

health issues started showing up in medical journals and case reports.

One of the first well-studied deaths was in 1924 in the UK. Nellie Kershaw, who’d been

spinning asbestos into yarn since she was 13, died at the age of 33 from asbestosis.

When Parliament heard about the case, they asked a doctor known as E. R. A. Merewether

to investigate the health of asbestos workers.

For two years, he studied 374 workers at an asbestos textile factory. He found that inhaling

asbestos fibers caused scarring in the lungs -- and 17 out of 20 workers who had been there

for more than 20 years ended up with asbestosis.

Merewether presented his paper to parliament in 1930, and the UK started requiring ventilation

in asbestos factories a year later.

But it wasn’t until 2003 that asbestos was banned throughout the European Union.

The asbestos industry in the United States is a whole other story.

Asbestos was used a lot during World War II, since it was cheap, strong, and resistant

to fire and chemicals. Naval war ships used asbestos insulation, and buildings were constructed

with asbestos floor tiles, shingles, cements, and insulation for pipes.

Production of asbestos in the United States finally started to slow down 1979, when nine

asbestos manufacturers filed a lawsuit against the federal government.

In 1975, they’d paid $69,000 to an asbestos worker who developed asbestosis, and they

wanted to be reimbursed.

But the government wouldn’t have any of that. Instead, they proved that the companies

knew about, and had been hiding, asbestos-related health information for decades.

The case got a lot of media attention, and people started to try to fix the problem by

removing asbestos from buildings. But the US still hasn’t entirely banned the use

of asbestos.

Even so, asbestos won’t cause health issues for most people.

Most of the fibers are so tightly bound into another material that they won't escape into

the air unless you’re trying to remove the asbestos.

Plus, every year we each breathe about a million fibers just from the natural erosion of asbestos-containing

rocks.

So unless you’re an asbestos worker who’s spent a lot of years without a ventilation

mask, or you’re an ancient Finnish potter, you probably don’t have to worry about getting

an asbestos-related illness.

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