Methylchloroisothiazolinone

Methylchloroisothiazolinone (CAS 26172-55-4), commonly known as CMIT or MCI, is a broad-spectrum biocide used to control microbial growth in water-based systems and industrial formulations. It is most effective against bacteria, fungi, and algae, making it a standard preservation active in both industrial and consumer product manufacturing processes worldwide.

In personal care and cosmetics, CMIT is used as a preservative in rinse-off products such as shampoos, conditioners, and liquid soaps, typically in combination with MIT as a blend. Industrial water treatment systems rely on it to prevent biofouling in cooling towers, process water circuits, and paper mill white water loops to maintain operational efficiency.

Coatings and adhesive manufacturers incorporate it into water-based paints, emulsions, and sealants to extend in-can shelf life and prevent spoilage during long-term storage. Oilfield and metalworking applications use CMIT-based biocides to control sulfate-reducing bacteria in injection water and cutting fluid systems to prevent equipment corrosion.

CMIT is supplied as an aqueous solution, most commonly as a 1.5% or 14% active concentrate, and is rarely handled as a pure substance due to specific stability requirements. It is available in technical grade, with supply typically governed by ISO or in-house specifications. Industrial packaging ranges from drums to IBC containers.