Ohio History Central, an online encyclopedia of Ohio history, explains that the Cuyahoga River fire in 1969 heightened awareness of how unregulated markets create socially undesirable outcomes, such as a polluted environment:
On June 22, 1969, an oil slick and debris in the Cuyahoga River caught fire in Cleveland, Ohio, drawing national attention to environmental problems in Ohio and elsewhere in the United States. This Cuyahoga River fire lasted just thirty minutes, but it did approximately fifty thousand dollars in damage — principally to some railroad bridges spanning the river. It is unclear what caused the fire, but most people believe sparks from a passing train ignited an oil slick in the Cuyahoga River. This was not the first time that the river had caught on fire. Fires occurred on the Cuyahoga River in 1868, 1883, 1887, 1912, 1922, 1936, 1941, 1948, and in 1952. The 1952 fire caused over 1.5 million dollars in damage.
On August 1, 1969, Time magazine reported on the fire and on the condition of the Cuyahoga River. The magazine stated: Some River! Chocolate-brown, oily, bubbling with subsurface gases, it oozes rather than flows. “Anyone who falls into the Cuyahoga does not drown,” Cleveland’s citizens joke grimly. “He decays”. The Federal Water Pollution Control Administration dryly notes: “The lower Cuyahoga has no visible signs of life, not even low forms such as leeches and sludge worms that usually thrive on wastes.” It is also — literally — a fire hazard.
Because of this fire, Cleveland businesses became infamous for their pollution, a legacy of the city’s booming manufacturing days during the late 1800s and the early 1900s, when limited government controls existed to protect the environment. Even following World War II, Cleveland businesses, especially steel mills, routinely polluted the river. Cleveland and its residents also became the butt of jokes across the United States, despite the fact that city officials had authorized 100 million dollars to improve the Cuyahoga River’s water before the fire occurred. The fire also brought attention to other environmental problems across the country, helped spur the Environmental Movement, and helped lead to the passage of the Clean Water Act in 1972.