The Clean Water Act is entering its 40th year of preventing rivers from catching fire.
The federal law may have come too late for Northeast Ohio's Cuyahoga River, which caught on fire in 1969, downstream from dozens of high-polluting factories. But since the Clean Water Act was passed in 1972, the state of waterways across the country has improved, and rivers and lakes once described as "dead" now host diverse forms of aquatic life.
The law's approach was radically different from environmental legislation that came before it, requiring tough national standards and outright banning dumping without a permit.
See the story at Slate.