Nonionizing radiation is used for disinfection and uses less energy than ionizing radiation. It does not penetrate cells or packaging. For example, UV light causes thymine dimers to form between adjacent thymines within a single strand of DNA. When DNA polymerase encounters the thymine dimer, it can incorporate the wrong nucleotide into the strand. (two adenines instead of an adenine and thymine) this leads to mutations that can ultimately kill the cells