The EPA's website has a wealth of information about the history of Earth Day and actions you can take to protect health and the environment throughout the year. Here's some background information from that website about the creation of Earth Day and the EPA.
First Earth Day in April 1970
Before 1970, factories could spew black clouds of toxic into the air or dump tons of toxic waste into a nearby stream, and that was perfectly legal. They could not be taken to court to stop it. This was possible because there was no EPA, no Clean Air Act, no Clean Water Act. There were no legal or regulatory mechanisms to protect our environment. In Spring 1970, Senator Gaylord Nelson created Earth Day as a way to "force this issue onto the national agenda." 20 million Americans demonstrated in different U.S. cities, and it worked! In December 1970, Congress authorized the creation of a new federal agency to tackle environmental issues, the U.S. Environmental Protection Agency.
Over 40 Years of Protecting Health and the Environment
In 1970, President Richard Nixon and Congress established the U.S. EPA in response to the growing public demand for cleaner water, air and land. EPA was tasked with the challenging goal of repairing the damage already done to the environment and to establish guidelines to help Americans in making a cleaner-and safer-environment a reality. Since 1970, EPA has been working for a cleaner, healthier environment for the American people.
For complete details about the events taking place on Earth Day, both in Washington, DC and around the country, visit the EPA's Earth Day website at http://www.epa.gov/earthday/index.html.