Methylisothiazolinone preservative molecule. Computer artwork showing the structure of a molecule of the biocide and preservative chemical methylisothiazolinone (MIT). MIT and other isothiazolinone-derived biocides are used to control microbial growth in water-containing solutions. MIT is often used in personal care products however, some studies have shown it to be allergenic and cytotoxic, leading to some concern over its use. Atoms are coloured coded: carbon (light blue), hydrogen (green), oxygen (red), sulphur (yellow), nitrogen (dark blue); with the bonds between them shown as rods.