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The “four zeroes” goal for the rectification of fine chemical enterprises refers to: eliminating risks associated with reaction safety assessments, completing the upgrade of automation control equipment, ensuring that all employees meet the required educational and qualification standards, and carrying out renovations in areas with high concentrations of people. This goal is part of the three-year action plan for improving the safety of hazardous chemicals, as well as part of the national efforts to address safety risks related to hazardous chemicals. It is also an important component of the special initiatives aimed at regulating the relocation of hazardous chemical industries. Today, the author will help everyone properly understand these “four zeros” from three aspects. 01 Why is it necessary to place special emphasis on the “four zeros” goal for the rectification of fine chemical enterprises? This is determined by the production characteristics of fine chemical enterprises. Most fine chemical production processes are operated on a batch or semi-batch basis. These processes are complex and variable, with rapid advancements and frequent changes in technology. The reactions involved are complex, with numerous side reactions; there are many different types of materials used, as well as numerous intermediate products and by-products. This demands high standards from the operators. Among these, identifying the risks associated with reaction heat, improving the level of automatic control, reducing the number of on-site operators, and enhancing the competence of those operators are key to preventing and controlling major risks in fine chemical enterprises. However, in recent years, accidents have occurred from time to time due to factors such as unclear identification of reaction heat risks, low levels of automatic control, and low educational qualifications among the personnel involved. In some cases, the presence of too many operators on site exacerbated the consequences of these accidents. For example, in the severe explosion and fire accident that occurred at Yibin Hengda Technology Company on July 12, 2018, there were issues such as the failure to conduct a reaction safety risk assessment for the diazotization process, testing being carried out directly on industrial equipment without automatic control or process interlocks, the fact that most of the operators in the affected workshop had only an elementary education or less, and an insufficient fire separation distance between the analysis laboratory and the nitration equipment. In the severe explosion incident that occurred on December 9 at Lianyungang Juxin Biotechnology Co., Ltd., no safety risk assessment was conducted for the nitration process. The insulation vessels, feeding systems for the dichlorobenzene production units, and the purification units were not equipped with automatic control systems. Moreover, as manual operations were used primarily, operators were present on each floor on a continuous basis; the vast majority of these operators had only an education level equivalent to junior high school or lower. 02 What does the “four zeroes” goal for the rectification of fine chemical enterprises include? The \"Three-Year Action Plan for Special Rectification of Hazardous Chemicals Safety\" sets clear requirements for the \"four zeroes\" goal regarding the rectification of fine chemical enterprises: (1) Zero in terms of reaction safety risk assessment. In addition to the fine chemical production processes that are included in the scope of safety risk assessment for chemical reactions and require evaluation, specific requirements are also set for fine chemical production facilities involved in nitration, chlorination, fluorination, diazotization, and peroxidation processes. First, it is necessary to complete a reaction safety risk assessment of the entire production process for the relevant products by the end of 2021 ； Second, conduct thermal stability tests on the relevant raw materials, intermediate products, products, and by-products ； Third, conduct risk assessments for unit operations such as distillation, drying, and storage. Among these, it is crucial to enhance the application of the results from safety risk assessments for fine chemical reactions. For processes for which such assessments have already been conducted, it is necessary to install appropriate safety facilities based on the level of reaction risk and the recommendations arising from the assessments, to improve safety control measures, to review and revise safety operating procedures in a timely manner, and to ensure that equipment and facilities meet the safety requirements of the processes involved. If the fine chemical production facilities fail to implement the recommended assessment measures, they must cease operations for rectification by the end of 2022. (II) Reset of the transformation of automated control equipment. First, for production facilities and storage installations that fall under the category of “two key areas and one major item,” the utilization rate of emergency shutdown devices and automated control system equipment must reach 100%; those that have not achieved this level or are not in use must cease operations for rectification. Secondly, efforts should be made to achieve full-process automated control for production facilities involving key hazardous chemical processing technologies; by the end of 2022, all upstream and downstream equipment associated with nitration, chlorination, fluorination, diazotization, and peroxidation processes must be under automated control. This goal is to minimize the number of people in the workplace. (III) Eliminate those whose educational qualifications and professional credentials do not meet the standards. It is primarily aimed at enterprises that have production facilities and storage installations related to the \"two key areas and one major concern.\" Starting from April 2020, the following personnel must first meet the required standards. First, for enterprises involving \"two key areas and one major facility\" in terms of production units and storage facilities, the newly appointed chief executives, as well as those in charge of production, equipment, technology, and safety, as well as safety management personnel, must have a college degree or above in related fields such as chemistry or chemical engineering, or hold an intermediate or higher professional title in the field of chemical engineering. Secondly, operators of production units and storage facilities involving major hazard sources and chemical processes that are under strict supervision must have a high school education or above, or possess an intermediate or higher level of vocational education in the field of chemistry. Third, operators of production facilities and storage installations involving chemicals with explosive hazards must possess an associate degree or higher in chemical engineering. As for the existing staff who do not meet the above requirements, they should reach the corresponding standard by the end of 2022. At the same time, hazardous chemicals enterprises are required to employ registered safety engineers with expertise in chemical engineering as stipulated. (IV) Achieve a \"zero\" status in the relocation and renovation of crowded places. It mainly refers to production facilities involving chemicals with explosive hazards, production facilities with Class A and B fire hazards, as well as factories (including facilities or workshops) and warehouses with Class A and B fire hazards, dust explosion hazards, and poisoning hazards. The facilities subject to relocation and renovation are control rooms, shift change rooms, offices, rest rooms, outdoor operation rooms, and inspection rooms. First, the control rooms and shift change rooms for production facilities that handle chemicals with explosive hazards must not be located within the facility area; those that have already been built and put into use must be rectified by the end of 2020. Secondly, control rooms and shift change rooms for production units involving Class A and B fire hazards should, in principle, not be located within the unit area. If it is necessary to locate them there, anti-explosion design, construction, and reinforcement must be carried out in accordance with the \"Code for Anti-explosion Design of Petrochemical Control Rooms\" (GB50779-2012), and this must be completed by the end of 2020. Third, offices, rest rooms, outdoor operation rooms, and inspection rooms located in factories (including installations or workshops) and warehouses that pose risks of Class A or B fires, dust explosions, or poisoning must be demolished by August 2020. 03 How to implement the “four zeroes” goal for rectifying fine chemical enterprises? First, it is necessary to correctly understand the meaning of the \"four zeros,\" and second, it is necessary to achieve dynamic zeroing. Dynamic zeroing is the biggest challenge; it is also why, in many areas, the data on companies that have been brought to zero status can reach nearly 100%, only for it to be found that some companies are still not at zero status upon further inspection. In the production process of enterprises, changes such as process optimization, equipment modification, and staff adjustments, if not managed properly through change control processes or if corresponding improvements are not made in a timely manner, will surely render the efforts made earlier to achieve zero defects useless. (1) Regarding the “zero-based” assessment of reaction safety, emphasis is placed on batch and semi-batch reactions in fine chemical enterprises that involve hazardous chemical processes under strict supervision as well as metal-organic synthesis reactions (including Grignard reactions). A reaction safety assessment must be conducted in any of the following situations: first, when a new process or formula is used for industrial production for the first time in China; or second, when a new process introduced from abroad has not yet undergone a reaction safety assessment ； Second, there are changes in the existing process routes, process parameters, or plant capacity, and there is no reaction safety risk assessment report ； Third, production safety accidents have occurred due to issues with the reaction process. It is particularly emphasized that reaction risk assessment should be carried out to determine the hazard level of the reaction process, improve the design of safety facilities, and enhance risk control measures. Among these, the application of the results from reaction safety risk assessment is crucial. To achieve a dynamic elimination of reaction safety risk assessments, it is necessary to recognize that when a company carries out process optimization or experiences changes in raw materials or auxiliary materials, since the process control conditions as well as the raw materials or auxiliary materials have changed, the company must conduct reaction safety risk assessments again. When an accident occurs during the operation of similar processes in the industry, the enterprise should analyze the root causes of the accident, and by conducting reaction safety risk assessments or material thermal stability tests on the identified process issues, determine whether the risks associated with the current process conditions are acceptable. (II) Regarding the “zero-deficit” goal for the renovation of automated control equipment, this requirement has two implications: first, the installation/construction rate of automated control system equipment must reach 100%; second, the utilization/usage rate of such automated system equipment must also reach 100%. What is included in a 100% coverage rate for automated control system equipment (installation/construction)? The author believes that in accordance with standards, regulations, and relevant policy requirements, there are at least the following aspects: first, installing automated control systems for facilities that involve hazardous chemical processes or highly regulated hazardous chemicals. Second, automated control systems that ensure the chemical production equipment associated with major hazard sources meets safety requirements. Third, the upstream and downstream equipment related to processes such as chlorination, nitration, fluorination, diazotization, and peroxidation must be under automated control. Fourth, for major hazard sources of level 1 or 2, an emergency shutdown system is required ； Hazardous chemicals tank farms with Level 1 or Level 2 major hazard sources shall be equipped with an emergency shutdown function ； Large and highly hazardous chemical plants should be equipped with emergency shutdown systems in accordance with the recommended control schemes ； Emergency shut-off devices are installed for key facilities such as toxic gases, highly toxic liquids, and flammable gases among the major hazard sources. Fifth, for chemical plants and hazardous chemical storage facilities that involve the \"two key areas and one major issue,\" a safety instrumented system should be installed on top of the SIL classification ； Hazardous chemical storage areas that constitute Class I or Class II major hazard sources involving toxic gases, liquefied gases, and highly toxic liquids shall be equipped with an independent safety instrumented system. Sixth, information such as temperature, pressure, liquid level, flow rate, and composition related to major hazardous sources of hazardous chemicals should be continuously collected and monitored, and the system must have functions such as remote data transmission, continuous recording, accident early warning, and information storage ； The electronic data recorded shall be retained for no less than 30 days. A 100% utilization rate of automated system equipment is the key to achieving the \"four zeros.\" This requires that the control system designed according to the plan can be put into operation properly, such as the proper functioning of monitoring instruments, control valves, and shut-off valves; the proper operation of various control interlocks; reasonable setting of alarm values and interlock values for control parameters so that they can function effectively; and proper establishment of the interlock logic relationships within the control system. The author believes that the following are the reasons why it is difficult to reset dynamically in the renovation of automated control systems: first, the renovation and improvement plan for such systems is unreasonable, as the accompanying processes have not been optimized. Currently, when fine chemical companies upgrade their control systems for the production process, they rarely carry out corresponding optimizations to the process itself. As a result, after the control system is upgraded, it fails to meet the requirements of the process operation, forcing some automatic controls to be reverted to manual operation. Secondly, after the modification of the control system, the operators are not accustomed to it, especially the veteran employees who have been working in these positions for a long time; they are used to manual operation on-site and are unable to handle the DCS. Meanwhile, it is difficult for the company to find operators who meet the requirements, so they have no choice but to disable the relevant interlocks. Third, when the control system fails or it is necessary to disable interlocks under special operating conditions, no approval procedures are carried out; and even if approval were sought, there is no corresponding plan. Fourth, many fine chemical enterprises are small in scale and find it difficult to hire technical personnel skilled in instrument automation to meet the requirements; they must rely on external experts or technicians provided by suppliers, which makes it hard to address abnormal conditions that may arise at any time during production. Fifthly, the upgrading of automatic control systems in hazardous chemicals enterprises has concentrated in recent years; the demand for instrumentation and automation professionals across society is far beyond what is available, and it is difficult to develop such talent in a synchronized manner. (III) The “zero” goal regarding the relocation and renovation of crowded areas involves control rooms, shift change areas, offices, rest rooms, outdoor operation areas, and inspection rooms. Among these, there are many discussions online regarding issues such as whether the control room in the plant area must be moved elsewhere and whether reinforcement should be carried out after an explosion resistance assessment. In the author’s view, the control room is the safest place for people to gather within the production area; what needs to be considered is whether it can withstand the strongest shock waves without being damaged in the event of a potentially catastrophic explosion in the production equipment, or in the case of a severe gas leak where the gas spreads over the greatest distance before an explosion occurs. Various uncertainties, such as how far the gas can spread and where the ignition source is located, determine the risk factors associated with control rooms that do not have explosion-proof structures. Therefore, the author has always believed that, provided the fire separation requirements are met, the distance between the control room and the equipment should be as short as possible to facilitate operation; hence, a blast-resistant control room is the preferred choice for the relocation and renovation of control rooms. From the perspective of dynamic zero-COVID policies, although most companies have moved crowded areas such as control rooms, shift change areas, offices, rest rooms, outdoor operation areas, and inspection rooms out of the plant area as required, or have strengthened their structures to make them explosion-resistant, the fact that some companies have not established rules limiting the number of people in certain areas still means that there is a risk of too many operators being present on site ； Alternatively, the utilization rate of the device’s automatic control system is low, requiring operators to perform manual operations on-site, which results in an excessive number of people at the site. (IV) To ensure that the educational and qualification requirements for employees are met, enterprises must carry out training to improve the safety skills of their employees, in accordance with the implementation guidelines for the action plan aimed at enhancing safety skills in high-risk industries ； A plan for improving educational qualifications should also be developed to enhance the qualifications of existing staff. However, some companies are moving too slowly, do not pay enough attention to this requirement, and there are also issues such as inadequate screening of new employees and frequent staff reassignments, which result in failure to meet the zero-tolerance standards. In summary, the task of achieving the “four zeros” in the reform of fine chemical enterprises is a long-term and arduous one that requires persistent effort and the combined actions of the whole society. First, enterprises must assume primary responsibility for fulfilling the \"four zeroes\" goal in the rectification of fine chemical enterprises, and regard these \"four zeroes\" as a means to improve the inherent safety of production facilities, enhance the competence of employees, and minimize the consequences of accidents. Second, authorities at all levels should strengthen supervision; in accordance with the arrangements of the Ministry of Emergency Management, they should carry out reviews to ensure the achievement of the “four zeroes” goal in the rectification of fine chemical enterprises, thereby promoting the safe development of the fine chemical industry in their respective regions. Thirdly, third-party agencies must practice self-discipline; the completion of tasks such as safety risk assessment, renovation of automated control systems, modification of crowded areas, and improvement of the educational qualifications of employees all requires the active involvement and effort of these agencies. Therefore, they must adhere to the red lines and bottom limits regarding safe production. Fourth, it is necessary to strengthen talent development, particularly that of professionals in instrument automation technology. The training programs aimed at improving the ability of hazardous materials companies to prevent work-related accidents should be made full use of in order to enhance the professional skills of employees