Final answer:
The Clean Air Act of 1970 has indeed been amended, most notably in 1990, to address new environmental challenges and introduce market-based mechanisms. The EPA oversees the implementation of these laws, which have significantly contributed to improving air quality in the United States.
Step-by-step explanation:
It is incorrect to state that the Clean Air Act of 1970 has never been amended since its enactment. While the act played a significant role in establishing a foundation for addressing air pollution and improving air quality across the United States, it has undergone several important amendments to strengthen its provisions and address emerging environmental challenges.
One notable amendment was in 1990, when Congress passed a comprehensive set of changes to address acid rain, urban air pollution, and toxic air emissions, among other issues. These amendments also introduced market-based approaches like cap-and-trade programs for sulfur dioxide. The Economic Protection Agency (EPA) continues to play a crucial role in overseeing these regulations and ensuring compliance with both the original statute and its amendments.
Moreover, the Clean Air Act is complemented by other significant legislation such as the Clean Water Act of 1972, which collectively contribute to the command-and-control framework of environmental regulation in the United States. Despite critiques from some economists regarding the costs and efficiency of command-and-control regulation, the benefits of these laws have been substantial in reducing pollution and protecting public health.