Why isn’t white phosphorus considered a highly toxic substance?

It’s not listed in the catalog; it should be considered highly toxic

Looking at the first paragraph of this, it seems that from economic, managerial, and production perspectives, although white phosphorus is highly toxic, there is no desire to impose too strict controls in certain areas. https://mp.wei*n.qq.com/s?__biz=MzkwODE3NTg1Mg==&mid=2247485199&idx=1&sn=a65181c696c2f4d2a4739247f82288ba&chksm=c0ccb78cf7bb3e9a960307330f366103927bb679d93690e4c489d99314d2b6b2d59e76418e05&scene=21#wechat_redirect The following is the AI’s response: Although the acute toxicity data for white phosphorus indicate an LD50 of 3.03 mg/kg, which is much lower than the standard for highly toxic chemicals as defined in the “Catalogue of Hazardous Chemicals (2018)” (an oral LD50 in rats of less than or equal to 50 mg/kg), white phosphorus is not classified as a highly toxic chemical in practice. This situation can be understood based on the following points: 1. **Comprehensive hazard assessment**: The classification of hazardous chemicals takes into account not only acute toxicity but also other hazard characteristics, such as physical hazards, environmental hazards, and long-term health effects. White phosphorus possesses the properties of spontaneous ignition, flammability, and slow oxidation in air; these physical and chemical properties may be given priority consideration during classification. 2. **Management and Usage Scenarios**: The classification and management of hazardous chemicals also take into account the practical feasibility in real-world applications as well as the necessity of such management. Although white phosphorus is highly toxic, its hazards can be effectively controlled through specific safety measures when it is used in strictly controlled industrial and research environments. 3. **Special control measures**: Although not classified as highly toxic, white phosphorus remains a hazardous chemical and is subject to strict controls. Due to its spontaneous ignition property and potential toxicity, it may be classified under other hazard categories, such as self-igniting substances or toxic materials, requiring specific storage and handling conditions. 4. **Policy and Standard Updates**: The classification standards for hazardous chemicals may change as scientific research progresses and safety management policies are updated. Perhaps when compiling the catalog, considering the overall hazards of white phosphorus and the complexity of its actual management, it was not listed separately as a highly toxic chemical. 5. **Risk management**: Safety regulatory agencies may believe that existing safety procedures and control measures can effectively reduce the risks associated with the use and storage of white phosphorus, which is why they place emphasis on the definition of highly toxic chemicals. In summary, although the toxicity parameters of white phosphorus meet the criteria for being highly toxic, its final classification takes into account a wider range of safety management factors, including physical hazards and risk management in actual handling, which explains why it is not classified directly as a highly toxic chemical.