If it passes, the cap-and-trade bill would be the biggest environmental bill in years.

The legislation aims to curb greenhouse gases by setting up a system of tradeable pollution credits.

With the help of Congressional Quarterly researcher Frances Symes, we've gathered a list of the biggest environmental bills over the past decades.

Federal Water Pollution Control Act (1948)

Authorized the Public Health Service to prepare strategies to reduce pollution in interstate waters and improve the sanitary condition of surface and underground waters.

Air Pollution Control Act (1955)

Authorized funding for the Public Health Service to conduct air pollution research.

Clean Air Act (1963)

Boosted funding for research and enabled federal and state officials to curb emissions of air pollutants.

Wilderness Act (1964)  

Authorizes Congress to set aside relatively untouched federal areas for protection and recreation and created a legal definition of wilderness in the United States.

Air Quality Act (1967) (PL 90-148)

Authorized enforcement procedures for air pollution problems involving interstate transport of pollutants.

Wild and Scenic Rivers Act (1968)

Established a National Wild and Scenic Rivers System to protect rivers with important scenic, recreational, fish and wildlife, and other values.

National Environmental Policy Act (1969)

Requires all federal agencies to formally consider the environmental impacts of major projects or policy decisions.  Established a Council on Environmental Quality to coordinate government antipollution efforts.