Sixty-five years ago, as scientists furtively built the world’s first atomic bomb, they disposed of dangerous, toxic waste at this six-acre dump in Los Alamos, N.M. Now, a cleanup crew is gingerly picking through the waste in an attempt to clean it up, a process paid for with $212 million in federal stimulus money.

In the 1940s, when scientists first assembled for The Manhattan Project, an Allied program to develop nuclear weapons, this dumpsite was just an isolated mesa in the desert. Now, a town has sprung up around it — including three businesses right across the street.

Ken Romero, a machinist at the Jona Manufacturing Company, recently observed a startling reminder of just how dangerous the site remains.

“You wonder what’s going on,” he told the New York Times. “One day we looked across the street and there was a guy in a full-body white suit, and he was just 100 yards away from us.”

The decontamination team consulted scientists at Los Alamos National Laboratory, who came up with worst-case scenarios regarding the danger of the chemicals at the site, known as Technical Area 21, and then blew up the equivalent amounts of dynamite to test their safety measures.

Officials are treating the area with extreme care, as they don’t even know exactly what they’re going to find under the layers of dirt and gravel. They suspect it may hold a truck that was contaminated in 1945 at the Trinity test site, where the first atomic bomb was detonated.

The Los Alamos site isn’t the only nuclear waste site slated for cleanup. Other sites that will benefit from the $6 billion nuclear cleanup program include the Hanford site in Washington and a Savannah River site in South Carolina.

But that’s just a drop in the bucket considering the hundreds of toxic waste sites that remain, which take up as much land as Delaware and Rhode Island combined. Clean up of all 107 sites is expected to take decades and up to $260 billion to complete.