Wachholz said it simply took researchers a lot of time to interpret the voluminous material, draw conclusions and summarize findings. Researchers know that in the aftermath of a nuclear explosion, the gamma rays and neutrons that explode from an atomic fireball cause acute radiation sickness, burns, cancer, cataracts and some other diseases. Unlike fallout, these rays cover a relatively limited distance. Their impact is dramatic and often immediate. The effects of fallout, however, can be more subtle.
Fallout rides prevailing winds and can cover much of a continent.
And fallout carries iodine 131, which naturally concentrates in the human thyroid gland. The thyroid uses iodine to make thyroxine and other hormones that regulate metabolism. Children who do not get enough iodine may not grow normally or fully develop mentally. The cancer-causing potential of radioactive iodine 131 remains a mystery. Studies done so far have been tantalizing and frustrating in equal measure.