A Dakota Access pipeline protester temporarily stopped a policy address by Environmental Protection Agency Gina McCarthy in Washington Monday.

The protester interrupted the event at the National Press Club by asking McCarthy if she was thinking about the Standing Rock Sioux Tribe Monday morning when she awoke in her warm home, while they were battling police to stop the oil pipeline from moving ahead in North Dakota.

The pipeline has become a national touchstone for environmental protests of all kinds, from environmental justice to climate change. The Sioux say the project would harm their only source of drinking water and destroy sacred sites.

After the protester stopped, the moderator said he wasn't in the habit of rewarding protesters but asked McCarthy to address the Dakota Access project and what EPA's involvement in it has been.

"I have been to Standing Rock," McCarthy said. "It is not an issue that is off our radar screen."

The U.S. Army Corps of Engineers, which has primacy over the pipeline with the Interior Department, has not signed off on a key easement to allow the pipeline to go under Lake Oahe near the tribe's reservation, despite two court rulings that allowed the pipeline to move ahead.

The Army Corps last week said it would be seeking new data and begin new discussions with the tribe, delaying the pipeline indefinitely.

Near the end of a question-and-answer session, another protester stopped McCarthy and the moderator's final remarks by holding up a bottle of brown water, saying fracking was harming drinking water.

"We don't blame you," the protester said. "We blame the ignorance."