A lot of the piping is treated and sealed such that they shouldn't be dumping their toxic particles into whatever they're piping around. But when you run a solvent through those pipes, it breaks down the seals and exposes the water to contamination.

Flint was a textbook case. The pipes had been used without issue for years, but only because the water they trafficked was properly treated and clean. When the state switched Flint's water source to a cheaper, dirtier source, it eroded the piping and released lead contamination.

That's not to even say these pipes shouldn't have been replaced decades ago, on principle. It is simply to say that we're seeing a compounding crisis through both misuse and neglect.