In 1969 it was not uncommon for American rivers to burst into flames.  Filled with sewage, oil, and agricultural waste, several major rivers were so polluted that they caught fire multiple times.

Here's the story of how the US almost destroyed its rivers, and how it eventually brought them back from the brink.


Sources:
Silent Spring by Rachel Carson

https://www.smithsonianmag.com/history/cuyahoga-river-caught-fire-least-dozen-times-no-one-cared-until-1969-180972444/]

https://www.pbs.org/newshour/nation/this-river-was-once-so-dirty-that-it-caught-fire-now-its-fish-are-safe-to-eat-again

https://www.nps.gov/articles/story-of-the-fire.htm