This is 99% invisible. I'm Roman Mars.

Caroline Fraser grew up on the beautiful Mercer Island in Washington State.

But despite the seemingly peaceful landscape, her memories of the area were long haunted by an inexplicable amount of death.

In the 1970s, when Caroline was a teenager, the infamous serial killer Ted Bundy committed

his first confirmed murders, not far from where Caroline lived.

Then there was the man who lived down the street, who blew up his house with his family

inside.

I mean, it was just this horrific and inexplicable thing, which I think just stayed with me

because I didn't understand it.

Over the following years, Caroline would learn of more deaths, some by murder and suicide,

others from car accidents while driving on the poorly designed

Mercer Island Bridge. To Caroline, it felt as if there was a dark cloud looming above her

corner of the world. And in fact, there was. The cloud was coming from a giant smokestack

just outside of Tacoma, Washington, and it was made up of lead,

arsenic, and asbestos.

The 70s and 80s were the heyday of the mining and smelting of heavy metals in America,

metals like copper, lead, and sink, which all released huge amounts of toxic fumes

into the air. The same time period saw another awful trend. A massive spike in serial killing.

These are two seemingly unrelated histories, but Caroline set out on a quest to see if there was

some kind of connection here between environmental pollution and

serial killing. She remembers seeing a specific article in a local paper that gave her this

nagging feeling. And it was basically a kind of encyclopedia of all the serial killers who were

...