2-Nitro-2-bromopropan-1,3-diol (bronopol) and UV-rays.
D006801:Humans; D010592:Pharmaceutic Aids / Q000633:toxicity*; D010787:Photosensitivity Disorders / Q000139:chemically induced*; D011310:Preservatives, Pharmaceutical / Q000633:toxicity*; D011409:Propylene Glycols / Q000633:toxicity*; D014466:Ultraviolet Rays / Q000009:adverse effects*
D010592:Pharmaceutic Aids; D011310:Preservatives, Pharmaceutical; D011409:Propylene Glycols; C006827:bronopol