Isothiazol-3(2H)-one is widely used as a biocide in industrial water systems, paints, adhesives, cosmetics, paper, and textiles due to its strong antimicrobial properties. It effectively inhibits the growth of bacteria, fungi, and algae, making it ideal for preserving water-based products against spoilage. It is commonly employed in cooling tower water and metalworking fluids to prevent microbial contamination that can lead to odor, degradation, and system fouling. Its fast-acting nature and broad-spectrum activity allow for low-dose applications, enhancing cost efficiency and reducing environmental impact. Due to its instability in pure form, it is often used in stabilized formulations such as methylisothiazolinone or combined with other biocides for improved shelf life and performance.