See also the Cuyahoga catching on fire. Water burning is quite a poster child.
It is worth noting that this probably had more to do with the awful state of the city sewage system, so the water was well known to be contaminated. Luckily we've improved somewhat with sewage (I think).
Although anecdotally I've had a local lake closed for weeks at least due to toxic red algae blooms related to run off from farms (I believe it's fertilizer runoff that's attributed to these blooms)