No airborne radiation had been detected as of about 10:30 a.m. Radiological surveys were continuing. Instructions for people to shelter in place were expanded from central Hanford to all of Hanford, including LIGO and the reactor areas along the Columbia River, after the aerial survey. No one is being allowed to enter the site beyond the security barricades. Earlier in the morning workers near Purex had noticed a 4-foot-by-4-foot depression that was 2 to 4 feet deep over the tunnel.