National Geographic : 1976 Oct
The sidewalks of hell, if doused with acid and cobbled by heat, might approximate this forsaken pond once used for trapping neu tralized coal-mine wastes (above). The reaction of air and water with pyrites in coal mines yields noxious compounds, including sul furic acid. These trickle down creeks to the Potomac's North Branch. One of the most foul, Mill Run (left)deposits blazing mineral stains called "yellow boy." Waters like these make life uncertain for semiaquatic newts (right).