On June 19 1962, just before midnight, the second high-altitude launch was attempted. The STARFISH Thor flew a normal course for about 59 seconds after liftoff. Then the rocket motor stopped and the Range Safety Officer ordered the missile and warhead destroyed. The missile was between 30,000 and 35,000 feet of altitude. A substantial amount of debris fell on and in the water around Johnston Island. . The Navy Explosive Ordnance Disposal and Underwater Demolition Team swimmers spent 2 weeks recovering debris from the lagoon waters around the Sand and Johnston Islands. The presumptive course of the rocket, based on the debris field, was northwest, paralleling the shore and passing over Sand Island. They recovered 251 pieces of the system, some of which were plutonium contaminated. The number of people exposed to the fallout from Starfish is unknown. Contamination was widespread.
This is the crew that worked on Sand Island in the early sixties and a shot of some of the buildings they lived and worked in. This is a scan of this area taken by the AEC in 1974 when they were looking for "so-called" hot spots" that resulted from the self-destruct of the Thor missile in the Starfish test. They found eight areas of nigh radiation. There is no coding on this map that indicates whether the black circles represent hot spots, or it is the white squares. You can see the shadows of the buildings, which include the mess hall. In 1996 a group of researchers from Boston University headed by Dr. Robert Lobel dragged a radiation detector along the bottom of the lagoon. The paper can be found here. the academic paper mainly concerned itself with measuring the sensitivity of the device. Lobel asked the government for funding for a more extensive study aimed at determining whether the lagoon was safe, but I don't think it was never funded. The authors remark: "The beach on Sand Island near the old LORAN generator station has been characterized most carefully due to its proximity to the area of highest fallout." I have never seen that map.