Little scholarship in environmental communication has considered the intersections between public participation and social movement. We fill this gap by discussing how public participation process can become sites of radical politics when publics employ disruptive or improper tactics, known as indecorous voice. Indecorum can be used to sustain protest matters beyond official forums, engage multiple audiences, and forge new identities among publics. We demonstrate the utility of indecorum through two case studies: Love Canal, NY where residents combat exposure to toxic chemicals, and Salt Lake City, UT, where publics challenge industrial expansion in a fight for clean air.