08/31/2011 at 07:00 AM EDT
Daryl Hannah was among 100 people arrested Tuesday in Washington, D.C., during a sit-in in front of the White House to protest a a massive expansion of a pipeline carrying oil from Alberta, Canada, to the Gulf of Mexico.
"I do believe we are in a time of crisis for so many things. And in times of crisis, you have to get engaged in the process. You have to walk your talk. Being arrested is something you never hope for. You don’t want to get arrested. But you know it's a risk you take," the Kill Bill
star, noting that "Civil disobedience is a long-heralded American tradition," told PEOPLE after paying a fine and being released.
"The majority of people who got arrested with me were moms, grandmothers and school teachers. Like me, they are standing up against this big corporation and saying, 'No.' "
Hannah, 50, whose two previous arrests related to environmental protests concerned urban gardens to coal mining," added: "Tar sands are the worst environmental atrocity. This pipeline would extend over the nation's largest freshwater aquafiers that 20 million people depend on for water.
"A third of the nation's irrigation water comes from there. What's going to happen when that pipeline leaks? We can’t take that risk."
The project to which Hannah and the others are opposed would expand an existing pipeline that now terminates in Oklahoma. Stretching more than 1,600 miles and twice the length of the Trans-Alaska system, the new pipeline would be one of the biggest in the country, reports CNN
The State Department is expected to give the project final approval by year's end.