The technique has been to mutate the genes by irradiation or chemicals.该技术是通过放射线照射或者使用化学方法使基因变异。Their cancers are not so clearly tied to radiation exposure.他们的癌症是否和接触放射线有关还不太明确。Examples of unsafe environmental conditions are noise, radiation, dust.不安全的环境条件，例如噪音、放射线和粉尘。