Tristel supplies disinfectant and contamination control products to the international healthcare sector and the food sector. The majority of revenues come from endoscopy cleaning products but other areas are becoming increasingly important. Export sales are also growing. The company's products are based on chlorine dioxide chemistry. They come under EC legislation called the Medical Devices Directive, if they are used to clean medical devices, or the Biocidal Products Directive if they are used as a surface or water disinfectant.