Lung-searing ozone smog plagues cities across the country where almost half the population lives. The Senate Environment Committee's program for cleaning up urban smog was severely weakened during closed door negotiations, making the bill weaker than current law in several key respects. For example, the substitute bill rescinded EPA's current mandate to adopt a smog cleanup plan if a state fails to act, weakened the ability of neighboring states and citizens to bring suit if a state plan is inadequate, and attached increased weight to cost considerations in the setting of emissions limitations on existing industries in polluted areas.

The Kerry-Wilson amendment sought to restore the federal mandate to step in when states failed to carry out their responsibilities, to assure the citizens' right to sue to counter urban smog, and to reinstate the current Clean Air Act's technology requirements for polluted areas. The motion to table the amendment passed with a vote of 53-46 on March 21. No is the pro-environment vote.