Workers' Defence Committee
In June 1976 Chojecki was one of the participants in the campaign to help the repressed workers of Ursus and Radom. As a result he was dismissed from his position at the institute and went on trial along with Bogdan Grzesiak, and two printers from the Polish Trade Agency, Jerzy Ciechomski and Wiesfaw Kunikowski on June 12, 1976. In the same year he was among the organizers of the Workers' Defence Committee ("KOR"). He initiated independent publishing activity and was responsible for the reproduction of the "KOR Communications" and "Information Bulletin of the KOR" underground newspapers.