vehicles, in this case, ten 4.5-ton tanks, The data have not yet been fully reduced and the results given herein are subject to modification in the final report, It should also be remembered that these results amply to the peculiar surface conditions of the test site and for an atomic weapon of a tower burst. detonated under the low-level conditions For weapons detonated at or below the surface, or at heights of 1,000 feet or more, the results presented here may not apply at all, b. Within the tanks, lethal radiation dosage was obtained through 750 yards; median—Lethal dosage through 1,000 yards; serious radiation sickness through 1,250 yards; moderate radiation sickness through 1,400 yards. The accelcrations imparted to vehicles up to 750 yards, and the resulting movements, would probably cause serLous if not fatal injuries te the operating crews, From 1,000 yards out, the acceler’ tions and resulting movements were of no significance, Witnin 1,000 yards, the rise in temperature of the interior walls and the risc in internal air pressure were found to bs of secondary importance when compared with other factors, Outside of 1,000 yards, these effects were of no significance. ec, With regard to physical damage of the vehicles, the majority of damage was limited to external accessorics and anpendages, The lisited amount of major dam- age resulted from the overturning of two tanks and the removal of a turret from anoth The type of maintcnance required to return the damaged vehicles to complete combat effectiveness is indicated below: 500 yards - Depot Maintenance for one tank; Organizational Maintenance for the other, 750 yards - Field and Depot Maintenance. 1,000 yards = Ficld and Organizational Maintenance, 1,200 yards anu vuyuii - No maintenance required, d. Some general conclusions concerning the tactical effectiveness of atomic weapons when employed against 45 ton tanks under the conditions of this particular 300-ft, tower detonation are: (1) Vehicles and their operating crews will not be affected beyond abow 1,500 yards from ground zcro, (2) Vehicles will have immediate 100% combat effectiveness beyond 1,000 yards from ground zoro, (3) Operating crews of vehicles located from 1,000 to 1,500 yards will errcounter no immediate combat casualties, They will, however, eventually suffer varying degrees of disability due to radiation