-13~ II. a REPORT ON TEE IODINE 131 HAZARD Fi.OM GHOnT-RANGE FaLLOUL 1 ROLUCED BY NUCLEAR TESTS AT THE NEVADA TEST SITE 1) - The problem This report is an inquiry into the hazard resulting from exposure of local populations, especialiy in the vicinity of the Nevada Test site to iodine 131 in frllout produced by nuclear explosions at that site. At the hearings of the Joint Congressional Committee on Atomic Energy held in 1957, Or. Lyle Alexander summarized the iodine 131 hazard briefly: "For a period of days following a heavy deposition of fresh fallout, iodine 131, which has a half life of 8 days, may be of importance in direct contamina- tion of vegatation. Radioiodune is selectively concentrated in the thyroid gland, where excessive accumulations cause. cancer and cell destruction. anjury to the gland may not ve detected unti? long after the iodine has decayed." The Federal Radiation Council, in its Report #4, states that "In the special case where nearly all of the annual intake (of iodine 131) could cone from exposure *2 abnormally high concentrations in a ical erea, nuclear expiosiss of low yielded. resulting frow a single the Council cecognized that some small nuncber o% individual infunts could conceivably receive doses Vi whole." 135 40 tines “he averace for tie area as a the hirhest average cose tc infant thyroids due primarily to one high excursion of levels in 192 was 620 millirems in Salt Lake City, where most of the dose did