Oil company Chevron and oil rig operator Transocean are already being sued by the state of Brazil over 2,400 barrels of oil spilled outside Rio de Janeiro in November 2011.

But Brazil’s oil workers weren’t content to sit back and let the public prosecutor handle everything, so the FUP oil workers union—Brazil’s largest oil workers federation—brought its own civil lawsuit against the companies on Tuesday.

According to court documents, the lawsuit seeks to stop Chevron from drilling and producing oil in the same offshore Frade field where the spill occurred.

Read more in the Chicago Tribune.