The message from protesters Tuesday was "Keep the Clean Air Act intact."
The demonstrators were calling on Senator Lindsey Graham to publicly commit to uphold the legislation.
Tuesday morning in Downtown Columbia, members of environmental group 1SKY stood outside Graham's office.
The activists say several lawmakers have been working to overturn key parts of the legislation ever since it passed 40 years ago.
Graham is not one of those lawmakers, however he is working with leaders on new legislation that would shred the act allowing congress to regulate carbon.
"We have to rely on the clean air act," says Tim Liszewski of 1SKY. "It's the law of the land and Supreme Court has specifically said that it must be enforced. You know, it's not like we can ignore existing law."
Critics claim the act has contributed to outsourcing and a decrease in corporate profits.