all as it
ascended, all shelter personnel were in or behind the shelters. Some
left the shelters after the initial flash to view the fireball. As a
precautionary measure, they had been advised to lie on the ground
before the blast wave arrived. Project personnel located beyond the
shelters, such as at the Base Camp and on Compania Hill, were also
instructed to lie on the ground or in a depression until the blast
wave had passed (1). However, the blast wave at these locations was
not as strong as had been expected.

In order to prevent eye damage, Dr. Bainbridge ordered the
distribution of welder's filter glass. Because it was not known
exactly how the flash might affect eyesight, it was suggested that
direct viewing of the fireball not be attempted even with this
protection. The recommended procedure was to face away from ground
zero and watch the hills or sky until the fireball illuminated the
area. Then, after the initial flash had passed, one could turn around
and view the fireball through the filter glass. Despite these
well-publicized instructions, two participants did not take
precautions. They were temporarily blinded by the intense flash but
experienced no permanent vision impairment (1; 17).

People as far away as Santa Fe and El Paso saw the brilliant light of
the detonation. Windows rattled in the areas immediately surrounding
the test site, waking sleeping ranchers and townspeople. To dispel
any rumors that might compromise the security of Project TRINITY, the
Government announced that an Army munitions dump had exploded.
However, immediately after the destruction of Hiroshima, the
Government revealed to the public what had actually occurred in the
New Mexico desert (12; 13).

Immediately after the shot, Medical Group personnel began the
radiological monitoring activities described in section 3.1.2. At
0815, when most of the monitoring activities were completed,
preparations began for entrance into the ground zero area. To
regulate entry into the area, a "Going-in Board" was established,
consisting of Dr. Bainbridge, the Chief of the Medical Group, and a
special scientific consultant. Its purpose was to determine whether a
party had a valid reason for entering the ground zero area. The board
functioned for three days.

Military police at Guard Post 4 and at three roadblocks set up along
Broadway controlled entry into the area. Guard Posts 3, 5, 6, and 7
were within 3,000 meters of groun