NEVADA TEST SITE

The following was released at 5 a.m., PDT, Monday, July 15:

"The Diablo experimental device designed by Livermore Laboratories was detonated at 4:30 a.m. PDT today from a 500 foot tower in Area 2, Yucca Flat, approximately 14 miles north of News Nob.

"Diablo, the seventh full scale nuclear detonation of the Plumbbob series, originally had been scheduled for firing on June 25. A change in the schedule moved the readiness date to June 28, when a non-detonation occurred. The shot was rescheduled for July 11, but was postponed one day for technical reasons and three days because of unacceptable weather.

"There were 25 experiments on the sequence timer, four civil effects projects, and 11 military effects projects with associated experiments.

"A total of 800 military observers, including 100 Canadians, observed the detonation from trenches from a distance of approximately 4,400 yards. The Army Signal Corps continued its cloud tracking experiments and Army Radiological Safety Teams were prepared to monitor equipment display areas to determine safe re-entry points during the morning.

"Forty aircraft had been scheduled to participate.

"Wind runs made as late as 4 a.m. indicated that the atomic cloud would be quickly blown apart into a dispersed air mass with early fallout on the test site and bombing range, across the northeasterly quadrant from Yucca Flat. The various segments of the cloud are expected to be blown generally north of east across Nevada into southeastern Utah, then to swing in a northerly direction toward Wyoming. Because wind speeds are very low at all altitudes it is anticipated that fallout readings outside the bombing range will not be available for seven or more hours.

"Sixteen men in an underground shelter about 2,000 yards from ground zero who conducted the manned station experiments reported to the Control Point that they had gone through the detonation safely and were continuing the exercise.