This is the account of Pfc Curtis Sandefur, 2d Marine Division, Fleet Marine Force, Atlantic, based at Camp Lejeune, North Carolina and what he witnessed during his deployment to Exercise Camp Desert Rock V. During the predawn hours on Saturday, April 18, 1953, Pfc Sandefur along with some 2,100 other U.S. Marines would begin arriving by military trucks to the Nevada Proving Ground. The NPG is just north of Camp Desert Rock with 1,350 square miles of desolate desert in a rough flat range with northerly high peaks. Las Vegas is located about sixty miles to the southeast. This early arrival allowed ample time for officers accompanying the troops to present a briefing over a public address system. They informed them that radiation levels were minimal and perfectly safe. Approximately10 minutes before denotation, outfitted in full battle gear, the Marines would be positioned in an open 6-foot-deep trench 3,660 meters south of ground zero. Pfc Sandefur was amongst other Marines positioned along the right side. Just minutes before detonation, they knelt and braced themselves against the ground zero side of the trench and then ordered to take cover. They would be instructed to close their eyes tight and place an arm in front of them, even though they would still see the light and feel the heat from the blast. At 4:35 am (PST) with the ground temperature of 7.7 degrees Celsius and relative humidity at 40 percent, a device named Badger was detonated from a 300-foot steel tower in Area 2. It had a yield of 23 kilotons, slightly higher than the bomb dropped on Hiroshima, Japan. The top of the mushroom cloud formed by Badger rose to an altitude of 36,000 feet. Badger was the sixth event of Operation Upshot-Knothole and gave the Marines the opportunity to investigate the capability of helicopters in transporting troops in an attack after the employment of a nuclear weapon. The explosion from Badger was so powerful it pierced the desert floor causing the earth to shake. It illuminated Las Vegas like daylight and was evident 500 kilometers to the southwest in Los Angeles. After the shock wave passed, the Marines left the trenches, formed up, and moved out in attack formation toward the objectives to the north. Though the dust raised by the shock wave was thick, the cloud formed by Badger was visible to the Marines as they moved forward to their objectives. A northeasterly surface wind of about ten to 15 knots from ground zero gusted across the right flank exposing Pfc Sandefur and other Marines to unprecedented and unanticipated radiation fallout. After proceeding less than 460 meters, these Marines had dosimeter readings exceeding 3.0 roentgens, half the allowable dose of 6.0 roentgens and were ordered back to the trench area and were not permitted to continue the maneuver.