The US Federal legslation written in 1969 that called for a unified national policy. The following is the Purpose from the actual text, which is available off of the EPA website.

The purposes of this Act are: To declare a national policy which will encourage productive and enjoyable harmony between man and his environment; to promote efforts which will prevent or eliminate damage to the environment and biosphere and stimulate the health and welfare of man; to enrich the understanding of the ecological systems and natural resources important to the Nation; and to establish a Council on Environmental Quality

The results of this legislation was the creation of a majority of US federal regulation of the environment;it created the need for further environmental legislation, such as the following:

The Clean Air Act of 1970 and its amendments The Occupational Safety and Health Act of 1970 The Endangered Species Act of 1973 The Clean Water Act of 1977