The Biden administration is set to close four wide gaps in the U.S.-Mexico border wall in an open area of southern Arizona near Yuma, to “address operational impacts” and “immediate life and safety risks.”

The four gaps are within an incomplete border barrier project—the former Yuma 6 project area near the Morelos Dam, according to a press release from the U.S. Department of Homeland Security (DHS). The area has become one of the busiest corridors for illegal crossings.

The border barrier project, which was operational under the Trump administration, was left incomplete after President Joe Biden in 2021 sent back $2.2 billion in border wall funds to the Department of Defense to be used for overseas defense construction projects.