All of the exposed persons were evacuated to Kwajalein as soon as the Task Force facilities would permit. But it was not until a week or so after the explosion that arrangements could be made for men with radiation measuring instruments to tour the atolls and determine what the levels of exposure had been. On the southern tip of Rongerik they measured the activity and calculated that the American servicemen had received approximately 78 roentgens. This was good news because a dosage of 50 to 100 roentgens is not lethal and only in rare cases leads to any sickness. In any event full recovery could be expected within a few days. As they prowled around Rongerik atoll, the measuring crew found places where the radiation levels had been much higher. At the northern end a person would have received more than 200 roentgens. On Ailinginae the measured values were comparable to those on Rongerik. The estimated dosage to the Ailinginae people was 69 roentgens. On Rongelap the situation was much worse. Measurements in the southern part of the atoll showed that the Rongelap people had gotten a dose of about 175 roentgens. Such a dose would not be fatal, but at least some of the people would probably be sick. The crew then went on to explore the rest of the atoll. As they moved north, the dose levels rose higher and higher. In the middle of the atoll, only ten or fifteen miles from the inhabited part, a person would have received 400 roentgens of radiation. At this level he would have a fifty-fifty chance of surviving. On the northern tip of the atoll, about thirty miles away, the dose would have been over a thousand roentgens. Such a dose means certain death in less than a month. The following table contains a summary of what happened: _Number _Time of _Time of _Dose of fallout evacuation (roentgens)_ persons_ after after shot shot (hours)_ (hours)_ Rongelap 64 4 to 6 51 175 Ailinginae 18 4 to 6 58 69 Rongerik 28 7 32 78 Utirik 157 22 65 14 Fortunate Dragon 23 4 200 On Kwajalein the Marshallese were cared for and underwent medical observation. As soon as possible their skin and hair were scrubbed with soap and water. The coconut oil in their hair made decontamination difficult.