Spc. Richard Leroy McKinley’s white marble headstone may look like the others in Arlington Cemetery, but his grave serves as a grim reminder of the first fatal nuclear accident in America. McKinley’s grave is the only radioactive grave in the cemetery. He was laid to rest in a double lead-lined casket and lowered into a 10-foot concrete grave encased in a metal vault with an additional foot of concrete poured atop his casket. McKinley’s family had to watch the eight-minute veteran’s funeral from 20 feet away. McKinley was born on December 2, 1933, in Union City, Indiana, but he grew...