Building toxic chemical plants in flood prone areas is another externality. Flood prone land is cheaper to buy, but costs the manufacturer “saves” are in fact transferred in space and time to neighbors and downstream water users when the next flood spreads the toxic chemicals far and wide.
Houston has a particularly heavy concentration of these risks, but industrial farms with sewage settling ponds and mines with settling ponds adjacent to water routes are scattered throughout the United States.
Source: NYT, 2/10/18.
