OPERATION HARDTACK I PPG Time 16 May 1955 1330 Sponsor: GMT 16 May 1958 0130 SITE: LASL/DOD PPG - Eniwetok -south by SSW of Irwin about 6,000 ft from the island nie 20t ki" ON 162° 10' 4b" Site elevation: HEIGHT OF BURST: & Sea level +500 ft under water TYPE OF BURST AND PLACEMENT: Underwater - Device suspended by a cable. Water depth 3,200 ft PLUME TOP HEIGHT: at 155 sec PLUME DIAMETER: REMARKS: at 155 sec 1,760 ft MSL 3,400 ft MSL "Nearly all of the total gamma dose occurred within 25 minutes after zero time and was due to the passage of alrborne radioactive material. Gamma doses in excess of 1O0Or occurred within the first 15 minutes at downwind distances less than 16,000 feet. In both ihstances the residual field due to deposited radioactive materiel was relatively insignificant, although radioactive foam may represent a radiological hazard." 206 oem TATE: TIME: Wahoo