Possibly the greatest amount of radioactivity will be needed in food sterilization and preservation. One may incorporate the activities into rods which will safely retain the materials but which will allow a considerable fraction of the penetrating gamma rays to escape. To sterilize food means to destroy all microorganisms. Many of these are radiation-resistant and may have to be exposed to 50,000 or more roentgens—that is one hundred times as much as would kill a mammal.[17] Such massive irradiation begins to affect the foodstuff itself. In some cases sterilization by irradiation changes the food more than would be the case by boiling it or freezing it. In other cases irradiation produces less undesirable side effects than any other methods. Another way to use radiation is the preservation of agricultural products. This need not be done by the difficult procedure of sterilization. It is enough to control pests and to prevent germination of the seeds which one is trying to preserve. Thus we need here approximately one per cent of the radiation that would be required for sterilization. By so little radiation the food is not altered to a noticeable extent. It is precisely in such processes, where great amounts of materials will have to be irradiated, that a substantial fraction of the fission products might find employment. In all applications care has to be exercised lest radioactive materials should inadvertently be scattered around. Where great amounts are needed as in food sterilization and preservation, caution has to be redoubled. That trouble may arise has been illustrated by an occurrence in Houston, Texas. Radioactive iridium¹⁹², which is a beta and a gamma emitter, was being used by a certain industrial concern to take X-ray pictures of metal parts. A shipment of this radioactive material in the form of powder pellets was being opened by remote control when compressed gas in the container exploded and scattered some radioactivity around. The area was shielded but some of the radioactive dust escaped to the rest of the building. The two men who were operating the remote control apparatus became contaminated. They washed themselves and cleaned up the area but did not report the incident. A few weeks later a standard radiation check showed that the plant was still radioactive. Company officials became worried and called in experts. At this late stage the plant was thoroughly decontaminated. The homes of the two men were also examined and were found to be slightly radioactive. The men and their families were temporarily moved out while their homes were being cleaned up. When they returned, neighbors and friends shunned them. The four year old son of one of the men lost his playmates. People were afraid to enter the houses. One of the houses was put up for sale but no one wanted to buy it.