Chlorine dioxide is a class A 1 disinfectant confirmed by the World Health Organization, and there are basically no by-products. As long as the concentration is not too high, it will not cause harm to the human body. In general, if a waterworks wants to use it, it needs to ask the manufacturer for a business license, a hygiene license for a production enterprise in disinfection products, a hygiene license document for products related to drinking water hygiene and safety at the provincial level, a notice from the Health Planning Commission and a list of products of the enterprise, a provincial disease control inspection report, a municipal disease control inspection report, other honorary certificates, a company profile publicity page, a product usage and dosage publicity page, etc. Some regions have different policies, and relevant regulatory authorities may need other procedures.