Hours before Thursday’s debate got underway, nearly a dozen Greenpeace activists rappelled off the Fred Hartman Bridge above the Houston Ship Channel in a nonviolent civil disobedience action that brought shipping traffic to a halt in the largest oil export channel in the United States. The protesters were calling for presidential candidates to support the Green New Deal and for a just transition away from fossil fuels. One of the activists, Piper, streamed the action live on social media.

Piper: “All of the major oil companies depend on this terminal. That includes Exxon, BP, Shell, Chevron. They all depend on this terminal, and right now we are shutting it down.”

By late Thursday, police had arrested at least 15 of the activists. The Harris County Sheriff’s Office says they’ll face a number of charges related to obstructing roadways and waterways.