One externalitiy -- unpaid cost -- of cars and sprawl, is cancer

It’s been more than a dozen years since the metaphorical alarm was first sounded, and yet the residents of Fort Chipewyan still don’t know what’s killing them.
What they do know is that there are still elevated rates of cancer in the northern Alberta community. They also know that nothing's been done to address the issue, despite community leaders asking for further investigation for years.
“It’s like a silent killer. You don’t know what it is that’s out there, what’s causing you to get sick,” said Chief Allan Adam, leader of Athabasca Chipewyan First Nation since 2007. Adam was in Ottawa last week campaigning, once again, to get answers for his community.

https://www.nationalobserver.com/2019/12/17/features/downstream-oilsands-death-cancer-comes-too-often