The substance is a known allergen.
MI has been used as a preservative in industrial products for many years but the use and thereby the population?s exposure to MI has in recent years been growing dramatically. This is partly due to the lack of approved preservatives and partly due to the allowed concentration of MI in cosmetics in 2005 which was increased by 25 times. Since 2010 allergic reactions to the substance in cosmetic products have been stated often and MI is the fifth most allergenic preservative today.
MI is however often combined with the preservative Methylchlorisothiazolinone (MCI) in cosmetic products. The name for the mix is ?kathon?. The mix ratio of methylchlorisothiazolinon and methylisothiazolinon is 3:1. Kathonis rated R43 which means that itcan cause hypersensitivity ifskin contact occurs. Concentrated forms of both substances can cause corrosion to the skin and eyes.
A wave of allergic reactions swept through Europe when Kathon was introduced as a preservative in cosmetics in the 1980?ies. This led to a limit in the use of Kathon and a concentration condition of 0.0015%. In spite of this cases of allergic reactions to the substances are still seen.