The whole story of the explosion at China Chengda Engineering’s Wuhai BDO project

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Investigation Report on the Major Production Safety Accident of the Reused Water Plant at Inner Mongolia Dongyuan Technology Co., Ltd., Constructed under the General Contracting of China Chengda Engineering Co., Ltd. At 19:01 on October 7, 2014, an explosion occurred on the second floor of the reused water plant under construction at Inner Mongolia Dongyuan Technology Co., Ltd., located in Wuda Industrial Park, Wuhai City. The accident resulted in 3 deaths (2 died on the spot, and 1 died 3 days later due to ineffective treatment), 2 people suffered serious injuries, and 4 people suffered minor injuries. The reused water plant and some of the equipment inside it were damaged, resulting in direct economic losses of approximately 7.436 million yuan. After the accident, the main leaders of the Wuda District Party Committee and the district government rushed to the scene immediately and activated the district-level emergency response plan. Hou Fengqi, Secretary of the Uhai Municipal Party Committee, and Bi Lifu, Mayor of Uhai, went to the scene in person to give specific instructions and make arrangements for the rescue operations. The Uda District **immediately established an accident investigation team to investigate the incident. Through intensive efforts to carry out rescue operations, at 19:45 all the injured were taken to hospitals for treatment, and at 20:37 the open flames were completely extinguished. On October 10, the incident was upgraded to a major work safety accident due to the death of one injured person. On the 12th, the People’s ** of Wuhai City established an accident investigation team headed by Yin Zhongqiang, the director of the city’s Work Safety Supervision Bureau, with members drawn from the city’s Supervision Bureau, Trade Union, Work Safety Supervision Bureau, Public Security Bureau, and the ** of Wuda District (the list of team members is provided in Attachment 1). The city’s People’s Procuratorate was also invited to send representatives to participate. Subsequently, through coordination by the Third Department of the **State Administration of Work Safety, the accident investigation team appointed 3 experts from Xinjiang Meike Chemical Co., Ltd., a company in the same industry, along with 4 experts from Wuhai City, to form an expert group (the list of expert group members is provided in Attachment 2) to participate in the accident investigation. In accordance with the principles of \"not letting go until the issues are resolved\" and \"being scientific and rigorous, acting in accordance with laws and regulations, seeking truth from facts, and focusing on practical results\", the accident investigation team, through on-site inspections, evidence collection, testing and appraisal, as well as expert evaluations, determined the sequence of events leading to the accident, its direct and indirect causes, as well as the casualties and property losses incurred. It identified the nature of the accident and the responsibilities involved, and put forward recommendations regarding the handling of the relevant responsible persons and units. At the same time, suggestions for accident prevention measures were put forward in response to the causes of the accident and the prominent issues identified. The following report is hereby prepared: I. Overview of the entities involved in the accident (1) The construction entity, Inner Mongolia Dongyuan Technology Co., Ltd. (hereinafter referred to as Dongyuan Technology), is located in the Wuda Industrial Park of the Wuhai Economic Development Zone. It was established in December 2008; its organization code is 68004902-6, and its business license number is 150300000005231. The enterprise is a private company, with Yu Haiming as its legal representative. Its registered capital amounts to 2 billion yuan. The construction project involves an annual production capacity of 100,000 tons of 1,4-butanediol (hereinafter referred to as BDO), 240,000 tons of methanol, 720,000 tons of calcium carbide, 700,000 tons of air-fired quicklime, as well as a power plant with four 50-megawatt units. Among these, the 240,000-ton methanol production facility has not yet been built. In September 2014, the project’s chief commander was changed from the legal representative Yu Haiming to the general manager Yang Dong. The company currently has 1,159 employees. It has 10 departments, including the Safety Production Department, the Engineering Department, and the Human Resources Department; the Safety Production Department employs 5 full-time staff members. The 100,000-ton per year BDO production project of Dongyuan Technology was approved for initiation in 2011 by the Autonomous Region’s Development and Reform Commission (via Document No. Nei Fa Gai Chan Ye Zhi 3702). In May of that same year, Dongyuan Technology signed an EPC contract (a contract for design, procurement, and construction) for this 100,000-ton per year BDO production project with China Chengda Engineering Co., Ltd. (hereinafter referred to as Chengda Company). On May 19, 2014, the project obtained the approval necessary for trial production (as indicated by the Inner Mongolia Autonomous Region Work Safety Bureau’s “Notice on the Filing of the Trial Production (Use) Plan for Chemical Construction Projects”, Document No. Meng Wei Hua Project Bei Zi 000014) ； On September 15, the 100,000-ton BDO plant began trial production. (II) Chengda Company, the general contractor for design and construction, was established in 1988. It is located at No. 279, Middle Section of Tianfu Avenue, Chengdu. It is a state-owned enterprise with a registered capital of 436.9 million yuan. Its legal representative is Cao Guang. The organization code is 20196546-6, while the business license number is 510100000070632. Business scope: Technical consulting, design, transfer, and development in the fields of chemicals, petrochemicals, light industry, and civil construction ； Procurement of equipment and materials ； Engineering supervision, etc. It holds a Class A comprehensive qualification for engineering design, with certificate number: A151000187. There are 1,261 employees currently, and the company has a Safety, Technology, and Quality Management Department staffed by 4 safety management personnel. In May 2011, Chengda Company established the Dongyuan Technology BDO Project Department and appointed Xu Gang as the project manager. (III) Subcontractors involved in the construction of the reclaimed water plant: 1. China Chemical Engineering 16th Construction Co., Ltd. (hereinafter referred to as 16th Chemical Engineering Construction), established in 1965 and located in Yichang City, Hubei Province; it is a state-owned enterprise with Li Jihua as its legal representative, and its registered capital is 121.85 million yuan. The company’s business scope includes general contracting for chemical and petroleum engineering construction, installation of mechanical and electrical equipment, installation of pipelines for chemical and petroleum equipment, as well as anti-corrosion and insulation installation projects. The company currently has 3,112 employees. Organization code number: 17756978-8; Business license registration number: 420000000047462; Construction enterprise qualification certificate number: A1094142050268; Work safety permit number: (E) JZ Anxu Zhi Zi 000240-03. In October 2011, Chengda Company entrusted the installation of the utility plant equipment to Shiliu Huahua Jian; Shiliu Huahua Jian established the Dongyuan Technology BDO project team and appointed Liu Ronggao as the project manager. 2. China Chemical Engineering Ninth Construction Company (hereinafter referred to as “Ninth Construction”) was established in 1995 and is located in Panjin City, Liaoning Province. Its legal representative is Xu Jian. The registered capital amounts to 100 million yuan. It is a state-owned enterprise with 1,261 employees. Its organization code is 12241023-5, and its business license registration number is 211100003038693. Its business scope includes the installation of chemical and petroleum equipment and pipelines, as well as specialized contracting services for pipeline projects. Work Safety License Number: (Liaoning) JZ Work Safety License No. 001122-8/8; Construction Enterprise Qualification Certificate Number: A1091121110202-9/4. In May 2011, Chengda Company contracted the installation work for the underground main pipeline network (including the water seal well located southeast of the recycled water plant, see Figure 2) and the chemical production facilities to Jiuhua Construction. Jiuhua Construction established the Dongyuan Technology BDO project team and appointed Tian Hongsheng as the project manager. (IV) Supervision Unit 1: Beijing Zhongheng Xinda Engineering Project Co., Ltd. (hereinafter referred to as Zhongheng Xinda), established in 2004 and located in Beijing, is a limited liability company. Its legal representative was Lin Zhensheng; on February 25, 2013, this role was changed to Lin Sen. The registered capital of the company is 10 million yuan. Business scope: Engineering supervision, engineering consulting, technical consulting, and technical services. Organization Code: 75823385-2. Business License Number for Enterprise Legal Person: 110105006397480. Qualification Certificate Number for Engineering Construction Supervision Unit: 110105006397480. In September 2012, Dongyuan Technology hired Zhongheng Xinda to supervise the equipment installation by the general contractor. Wang Jingye served as the chief supervision engineer for the BDO project team; in July 2013, he was replaced by Zhu Zhongye. 2. Inner Mongolia Collin Construction Project Supervision Co., Ltd. (hereinafter referred to as Collin Supervision) was established in 1998 and is located in Haibowan District, Wuhai City. It is a limited liability company; its legal representative is Tian Maolin, and its registered capital is 3 million yuan. Business scope: Engineering supervision, engineering supervision consulting. Organization code number: 70126092-1; Business license number for corporate entities: 150302000029108; Qualification certificate number for engineering construction supervision units: 150302200813. In April 2012, Dongyuan Technology hired Colin Supervision to oversee the civil engineering work carried out by the general contractor; Tian Dong served as the chief supervision engineer for the BDO project department. II. Course of the accident and emergency response and aftermath handling (1) Course of the accident: The BDO production unit of Dongyuan Technology is the first production unit in China with the highest output per unit. In accordance with the requirements set forth in the environmental impact assessment approval issued by the Autonomous Region’s Environmental Protection Department for this project, the first wastewater treatment system in China was designed and installed. In September 2012, Chengda Company purchased a complete set of wastewater reutilization systems from Sichuan Aohesheng Environmental Protection Technology Co., Ltd. (hereinafter referred to as Aohesheng), and signed the \"Technical Appendix to the Unit Contract for the Wastewater Reutilization System in the Integrated Project for the Production of 100,000 tons per year of 1,4-butanediol at Inner Mongolia Dongyuan Technology\". Subsequently, Aohesheng submitted to Chengda Company, the general contractor, process design documents such as the process flow diagram, piping and instrumentation diagram, and pipe layout diagrams, all of which had been approved by Chengda Company. In May 2013, the Environmental Protection Department of the autonomous region approved the revised environmental impact assessment report for this project, requiring that the water collection methods and wastewater treatment capacity be adjusted accordingly to the changed drainage methods and volumes; furthermore, the treatment processes for inorganic and organic wastewater should be optimized so that the effluent meets the standards set in the \"Integrated Wastewater Discharge Standards\" (GB8978-1996), specifically the first-class standard limits. In June, in order to meet the requirements set out in the environmental impact assessment approval and to eliminate the risk of excessive discharge of reverse osmosis concentrated wastewater, Pan Wanlin, the person in charge of the company’s water supply and drainage operations, organized a meeting with designers, reviewers, and inspectors such as Zhang Ziwu, Jin Qinglin, Mao Ping, and Gu Xiulian. At this meeting, it was decided to change the direction of the overflow pipes; the 6 overflow pipes in the 6 water treatment tanks included in the Aohesheng complete set of technical equipment were to be connected to the underground sewage main instead of the rainwater system. The machine pumps in the basement of the recycled water facility were installed on February 28, 2014; the civil engineering work was completed in May, while the installation of equipment and pipelines was finished in mid-June. The lighting facilities were approved for use on August 4, and the operators responsible for water treatment, wastewater management, and air compression in the BDO division moved into the control room on the second floor of the recycled water plant on September 5. The power plant wastewater and high-salinity circulating water flowing into the reclaimed water plant have been connected; the instrument air has also been connected but not put into service. To test the performance of the pumps in the installed reclaimed water plant, high-concentration brine from the thermal power plant was pumped into the plant four times between September 25th and 29th (1,000 cubic meters on the 25th, 1,500 cubic meters on the 26th, 800 cubic meters on the 28th, and 500 cubic meters on the 29th; a total of 3,800 cubic meters). Inside the reclaimed water plant, there are a total of 9 pipelines connected to the outside world. Specifically, there is one inlet pipeline each for the concentrated water from the demineralized water station and the circulating water effluent pipe ； Water outlet pipelines: 1 pipeline for supplying water to the circulating water system, and 6 overflow pipes that converge and are connected to the plant’s main sewage pipeline (the pipelines connecting the reclaimed water plant to the outside world and the fluid flowing within these pipelines are described in Appendix 3: Expert Technical Assessment Report). On the day of the incident, the reclaimed water plant was in the construction phase, such as heating installation, and was not yet in use. In April 2014, the residential area of the Dongyuan Technology Project was put into use, and domestic sewage began to be discharged into the main sewer line. In June, Dongyuan Technology organized the preparation of a trial production plan, with the participation and cooperation of companies such as Chengda Company, 16th Chemical Construction Company, 9th Chemical Construction Company, Zhongheng Xinda, and Collin Supervision. In July, the water seal wells installed on the plant’s underground sewage network were not completed due to the inability to obtain PE tees; they were later filled in and thus lost their function as water seals. On September 15, following the start of trial production with feedstock input, samples taken from the BDO plant, residues analyzed in the laboratory, and wastewater generated by equipment and processes all flowed into the sewage treatment plant through the main sewage pipeline. Combustible gases such as methane and hydrogen present in the underground sewage pipeline could pass unimpeded through the unfinished WW29 water seal well, and then flow back into the recycled water plant via 6 overflow pipes. At 16:00 on October 7, Ding Bingwen and Feng Daxu, the main operators in charge of water treatment for Dongyuan Technology’s utility systems, along with inspection workers Zhang Xuelong, Zhuang Chunli, Mao Shuanxi, and Qiao Na, were on duty in the control room located on the second floor of the recycled water plant. At around 18:40, Feng Daxu, Ding Bingwen, and Zhang Xuelong went to the comprehensive pump station to open the valves of the rainwater wells in order to drain the water. At around 18:50, Jona went to the circulating water pump room together with Ding Bingwen and Feng Daxu to refuel Pump A of the circulating water system. After refueling, Feng Daxu returned to the control room at around 7 p.m. He saw that it was completely dark inside with no lights on. He then went to the first-floor entrance to turn off the main switch as well as the lighting circuit breakers for the first and second floors. Afterwards, he returned to the analysis room (which also served as a break room) next to the control room, intending to turn on the lights and have some water. At 19:01:24, the moment Feng Daxu turned on the switch, a flame shot out and ignited the combustible gases accumulated in the recycled water plant. Feng Daxu let out a scream as he fell to the ground, followed by an explosion. The accident caused Feng Daxu to suffer 37% second-degree burns across his body. The shock waves from the explosion threw Zhuang Chunli, Zhang Xuelong, and Mao Shuanxi, who were in the control room on the second floor, to the east side of the recycled water plant on the first floor. Zhuang Chunli died on the way to Wuda Central Hospital, while Zhang Xuelong suffered 50% third-degree burns across his body. Mao Shuanxi died at Wuda Central Hospital on October 10 after unsuccessful attempts to save him. Ding Bingwen and Jona, who were returning to the water treatment plant, were hit by the shock wave from the explosion. Ding Bingwen instinctively pushed Jona to the ground; he suffered minor injuries to his head and right leg. Operator Yang Jianguo was affected by the blast wave in the hydrogen production chemical dosing room and suffered minor injuries to his head. The shock wave from the explosion pushed Cui Mingxin, Lü Hai, and Zhang Guosheng, who were working on the first floor as heating installers for 16th Construction Company, toward the east side of the reclaimed water plant; as a result, Cui Mingxin died on the spot, Lü Hai was seriously injured, and Zhang Guosheng suffered minor injuries. (See Attachment 4 for the personnel position diagram before and after the explosion). The explosion center is located on the second floor of the recycled water plant, about 13 meters away from the south wall and about 12 meters away from the west wall, above the regulating tank on the first floor and the first intermediate tank on the west side. The explosion created an irregular depression with a diameter of about 6 meters at the impact point, covering an area of approximately 27 square meters. The blast wave caused by the explosion severely damaged the reclaimed water plant, while causing partial damage to the nearby air compressor station, substation, integrated pump station, and utility tunnel. The explosion also ignited the reverse osmosis filter elements stored in the analysis room on the second floor of the recycled water plant, with a total burned area of approximately 150 square meters. (See Attachment 5 for a schematic diagram of the blast’s impact area.) (II) Accident reporting: After the accident occurred, the entire plant of Dongyuan Technology lost power, and the automatic interlock system triggered an emergency shutdown. The company immediately activated its emergency response plan; at 19:03, Units 6 and 9 for producing calcium carbide as well as the raw material processing area were shut down, and the company’s own generator set was also stopped at 08:00. At around 19:20, Liu Baoliang, the deputy manager of the company’s Safety and Environmental Protection Department, called to report to the Wuda District Work Safety Supervision Bureau. At 19:24, the Wuda District Work Safety Supervision Bureau reported the situation to the Wuda District People’s ** level by level ； At 30 minutes, the People’s ** of Wuda District reported the matter to the People’s ** of Wuhai City and relevant departments. (III) Accident emergency response and rescue process: After the accident occurred, at around 19:08, the company’s emergency response team arrived at the scene and began providing first aid to the injured and carrying out search and rescue operations. At 19:45, all the injured were transported to Wuda Central Hospital for treatment. At 20:13, upon receiving the alarm, the command center of the Wuhai Fire Brigade promptly dispatched 7 fire trucks and 30 firefighters to the accident site to handle the situation. At around 20:22, ambulances and medical staff from Wuda Central Hospital rushed to the scene to immediately provide emergency treatment to the injured. At 20:37, all open flames were extinguished, and search and rescue personnel used radar life detectors as well as audio-video life detectors to search the area further for those trapped. At 2:32 a.m. on the 8th, the search and rescue operation came to an end. To provide the patients with better treatment conditions, Lu Hai, Zhang Xuelong, and Feng Daxu were successively transferred to the Ningxia Affiliated Hospital for treatment (see Attachment 6 for the list of those injured or killed). (IV) Post-incident handling: The people’s government of Wuda District promptly organized departments such as civil affairs and health to assign dedicated personnel to monitor the treatment of the injured at Wuda District Central Hospital, the Municipal People’s Hospital, and the Ningxia Affiliated Hospital. Dongyuan Technology and Shiliu Hua Jian each sent two deputy general managers and project supervisors to be responsible for the treatment of the injured and providing comfort to them. The Municipal People’s Hospital actively invited experts from Beijing to provide consultation and treatment for the injured. On October 19, the 16th Chemical Construction Company and Dongyuan Technology each signed compensation agreements with the families of Cui Mingxin, Mao Shuanxi, and Zhuang Chunli, thereby completing matters such as compensation payments for the deceased and the cremation of their remains. In accordance with the requirements of the Interim Measures for the Assessment of Emergency Response to Production Safety Accidents (Document No. An Jian Zong Tang Ying Ji [2014] 95), the accident emergency response assessment team conducted an evaluation of the emergency measures taken in response to the accident, and prepared the Assessment Report on the Emergency Response to the Serious Production Safety Accident that occurred on October 7th at the wastewater treatment plant of Inner Mongolia Dongyuan Technology Co., Ltd., which was constructed under the general contracting of China Chengda Engineering Co., Ltd. (see Attachment 7). III. Casualties and direct economic losses caused by the accident: The accident resulted in 3 deaths, 2 severely injured individuals, and 4 slightly injured persons. The direct economic loss amounted to approximately 7.436 million RMB. Of this amount, 4.247 million RMB was spent on medical treatment, funeral arrangements, and other post-accident expenses for the victims, while property losses totaled 3.189 million RMB. (Appendix 8 shows the table of direct economic losses resulting from the accident.) Table of basic information on those injured or killed: Name, Degree of injury, Gender, Age, Occupation, Length of service, Type of employment, Place of origin, ID number, Status of third-level safety training, Affiliated company. Cui Mingxin – Dead, Male, 61 years old, Plumber, 3 months of service, Temporary worker, Wuhai, Inner Mongolia. ID number: 150304195402024011; No training received. Shiliu Hua Jian. Zhuang Chunli – Dead, Female, 36 years old, Gas operator, 6 months of service, Contract worker, Wuhai, Inner Mongolia. ID number: 150304197802061021; Training received. Dongyuan Technology. Mao Shuanxi – Dead, Male, 25 years old, Operator, 15 months of service, Contract worker, Zhongning County, Ningxia. ID number: 640322198907130613; Training received. Dongyuan Technology. Lv Hai – Seriously injured, Male, 48 years old, Plumber, 3 months of service, Temporary worker, Bayannur City, Inner Mongolia. ID number: 152801196611226212; No training received. Shiliu Hua Jian. Zhang Xuelong – Seriously injured, Male, 26 years old, Water treatment operator, 20 months of service, Contract worker, Wuhai, Inner Mongolia. ID number: 152527198811124217; Training received. Dongyuan Technology. Ding Bingwen – Slightly injured, Male, 23 years old, Control operator, 14 months of service, Contract worker, Lingwu City, Ningxia. ID number: 640382199107021313; Training received. Dongyuan Technology. Feng Daxu – Slightly injured, Male, 24 years old, Operator, 14 months of service, Contract worker, Shizuishan, Ningxia. ID number: 640202199008280515; Training received. Dongyuan Technology. Yang Jianguo – Slightly injured, Male, 31 years old, Operator, 15 months of service, Contract worker, Wuhai, Inner Mongolia. ID number: 150304198307180511; Training received. Dongyuan Technology. Zhang Guosheng – Slightly injured, Male, 31 years old, Plumber, 3 months of service, Temporary worker, Wuhai, Inner Mongolia. ID number: 150304198302054057; No training received. Shiliu Hua Jian. IV. Causes and nature of the accident (1) Direct cause: Combustible gases such as methane and hydrogen in the underground sewage main pipes entered the wastewater treatment plant under construction through six overflow pipes, due to the “chimney effect”. Gases such as methane and hydrogen have a lower density than air, so they tend to accumulate in higher areas. Additionally, the exhaust fans on the second floor of the recycled water processing facility are not in use, and the windows remain closed, resulting in the formation of explosive mixtures within the relatively enclosed factory space. These mixtures accumulate over time until they reach their explosive limit. When the on-duty operator, Feng Daxu, turned on the lighting switch on the second floor, arcing at the switch triggered an explosion in the gas-filled area. (II) Indirect causes
1. Chengda Company, the general contractor and design unit, failed to conscientiously fulfill its primary responsibilities regarding design and overall safety in construction. Its design management and quality control were inadequate, and safety management at the construction site was insufficient.
(1) When implementing the design change to alter the flow direction of the overflow pipes, the company did not conduct a thorough risk identification and assessment regarding the connection of the overflow pipes from the reclaimed water plant to the underground sewage main. It also failed to strictly adhere to relevant provisions of the “Code for Fire Protection Design of Petrochemical Enterprises” by failing to install anti-backflow prevention devices such as water seals on the six overflow pipes or the collecting main. (2) Engineering safety and quality management are inadequate. The responsibilities for reviewing documents and conducting on-site inspections of the plant’s underground sewage network were not properly fulfilled ； No effective barriers have been put in place for the under-construction reclaimed water plant and the underground sewage pipeline network that has already been put into trial operation ； The intermediate handover was a mere formality; concealed works such as water seal wells were filled in before completion, and this was not detected or stopped in a timely manner. (3) Failing to properly fulfill the safety management responsibilities toward subcontractors in accordance with the general contract, and failing to provide adequate supervision over their safety. The frequent personnel transfers between the BDO project department and the staff of the Ninth Chemical Construction Company went unnoticed and uncorrected; procedures such as proper handovers, documentation, and technical briefings were not diligently carried out, thus creating potential safety hazards. 2. Jiuhua Construction fails to properly fulfill its responsibilities regarding work safety; there is laxity in construction quality and safety management: (1) The project department’s safety management is inadequate, with frequent staff changes, and proper procedures for task handover and technical instructions during construction are not followed. In July 2012, the construction manager was changed from Wang Zhengxin to Zhang Zhenjiang ； The head of the engineering department has been changed from Sun Cheng to Liu Lian ； In May 2013, the chief engineer was changed from Tong Yuhua to Wang Wei; neither of them carried out proper work handover procedures, nor did they inform the general contractor and the supervision unit or provide them with construction technical instructions. As a result, the water seal well was filled in before completion of the construction work, creating potential hazards. (2) Lax management of construction safety and quality. Upon on-site inspection of the WW29 water seal manhole on the underground sewage main, it was found that the tee fitting was not installed as per the design requirements, thus failing to serve its purpose as a water seal. (It was confirmed that the other three water seal wells on the sewage main pipe also did not have tees installed as required by the design.) The Jiuhua Construction Project Department failed to comply strictly with the relevant provisions of the \"Regulations on Quality Management of Construction Projects,\" and did not enforce proper quality inspection procedures; moreover, before concealing certain construction elements, they failed to notify the project owner and the construction project quality supervision agency. In cases where concealed works such as water-sealed wells were not constructed in accordance with the plans, no barriers or seals were put in place, no warning signs or fences were installed, construction planks were used to cover them, and no technical instructions were provided to the relevant parties. Intermediate handover procedures were carried out without proper documentation and on-site inspection and acceptance processes, and no objections were raised to the commencement of trial production for the BDO project, thereby creating potential hazards. 3. The safety management at the construction site of the 16th Chemical Construction Company was lax and inadequate, with the following deficiencies: (1) As a specialized company in the installation of chemical and petroleum equipment and pipelines, it failed to raise any objections regarding the discrepancy between the construction drawings for the reclaimed water process and the layout plan of underground pipelines. (2) After the construction of connecting the six overflow pipes to a manhole, no consideration was given to installing a blocking/cut-off device prior to its handover and use. 4. Supervisor Colin failed to fulfill his supervision responsibilities properly: (1) He did not ensure that concealed works such as water seal wells constructed by Jiuhua Construction were completed in accordance with the plans; no barriers or sealing measures were put in place, no warning signs or fences were installed, and no written reports or technical instructions were provided to the relevant parties – supervision was inadequate. (2) Failure to strictly follow the work handover procedures for the personnel transfer at Jiuhua Construction, as well as neglect in providing construction technical instructions, resulted in the water seal well not being constructed properly and thus being filled in, failing to serve its purpose as a water seal. 5. Zhongheng Xinda failed to properly fulfill its responsibilities regarding construction quality and safety supervision: (1) It appointed Zhu Zhongye, who does not possess the qualifications of a registered supervision engineer (he only holds a certification as a chemical supervision engineer issued by the Chemical Supervision Branch of the China Construction Supervision Association), as the project director for the BDO project. (2) As a professional supervision company, it failed to raise any objections to the discrepancy between the construction drawings for the reclaimed water treatment process and the floor plans of the underground pipelines. It also failed to detect in time that there were no water seals or other devices designed to prevent backflow on the 6 overflow pipes in the reclaimed water treatment plant, nor on the main pipe that collects these overflow pipes. Moreover, it failed to implement effective safety measures such as proper isolation between the reclaimed water treatment plant, which was under construction, and the sewage pipeline network that had already started trial operation. No objections were raised regarding the start of trial production. 6. Dongyuan Technology failed to properly fulfill its responsibilities as the construction party with regard to quality and safety management: (1) It did not exercise proper oversight regarding the installation, pressure testing of sewage pipelines throughout the plant, as well as other concealed works such as water seal wells; it signed and sealed the handover certificates without conducting effective supervision and inspection, and failed to ensure that the supervision unit carried out adequate inspections. (2) Insufficient safety inspections were carried out on the underground sewage pipeline network put into trial operation, failing to detect in a timely manner the risk of hidden elements such as unfinished water seal wells being filled in ； No strict requirements were placed, nor were inspections carried out, to ensure that the general contractor implemented effective safety measures such as proper barriers for the wastewater reutilization plant under construction and installation, as well as for the underground systems for treating domestic and industrial wastewater that are set to enter trial operation. 7. The Inner Mongolia Autonomous Region Petroleum and Chemical Engineering Construction Quality Supervision Station (hereinafter referred to as the Petrochemical Supervision Station) failed to fulfill its responsibilities for quality supervision: the Petrochemical Supervision Station is responsible for examining the qualifications of the construction and supervision units and personnel involved in the Dongyuan Technology BDO project, as well as the compliance of the project contracts. The relevant provisions of the Regulations on Quality Management of Construction Projects were not strictly implemented; the risks and issues associated with Zhu Zhongye from Zhongheng Xinda holding the position of project director without having the qualifications of a registered supervision engineer were not identified or addressed. 8. Inadequate safety management by the Uda District Housing and Construction Bureau: The Uda District Housing and Construction Bureau held oral discussions with the Petrochemical Supervision Station regarding project safety supervision. However, since the Petrochemical Supervision Station was only responsible for overseeing the quality of industrial plant construction and equipment installation, and not for safety supervision, the bureau failed to urge this station to assume its safety supervision responsibilities in accordance with the principle that those in charge of a particular task must also be responsible for ensuring safety. Nor did it take timely action to establish such safety supervision mechanisms. 9. The Wuda District **failed to fulfill its responsibilities for local supervision, and failed to ensure comprehensive safety oversight of industrial construction projects. (III) Determination of the nature of the accident: Upon investigation, it was determined that the \"10·07\" explosion incident that occurred at the wastewater treatment plant of Inner Mongolia Dongyuan Technology Co., Ltd., a project supervised by China Chengda Engineering Co., Ltd., was an industrial construction project safety liability accident. V. Analysis of accident responsibilities and recommendations for handling (I) Recommendations for administrative sanctions and penalties against certain individuals: 1. China Chengda Engineering Co., Ltd. (1) Zhang Ziwu, the design staff member responsible for the BDO project at China Chengda Engineering Co., Ltd., is accountable for the quality of the designs as well as the schedule for their completion, ensuring that the designs meet the required depth of detail. It violated the requirements set out in the company’s \"Work Standards for Designers, Reviewers, and Approvers\" (hereinafter referred to as the \"Work Standards\"), which call for strict compliance with current standards, regulations, and unified engineering specifications. When implementing the design changes to the route of the overflow pipes, no barrier devices such as water seals were installed on the 6 overflow pipes or on the main pipe through which they converge, in accordance with the relevant provisions of the \"Code for Fire Protection Design of Petrochemical Enterprises.\" Nor was any identification of hazardous factors carried out. This person is directly responsible for the occurrence of this accident; given that their actions may constitute a crime, it is recommended that they be handed over to the judicial authorities for prosecution in accordance with the law. (2) Pan Wanlin, the person in charge of the water supply and drainage design for the BDO project at China Chengda Engineering Co., Ltd., is responsible for the design of the water channels and underground pipes for the project. When organizing professional personnel to revise the design for the layout of the overflow pipes, only environmental protection risks were taken into consideration; the designers were not required to install blocking devices such as water seals on the 6 overflow pipes or the main collection pipe for these pipes, in accordance with the relevant provisions of the \"Code for Fire Protection Design of Petrochemical Enterprises\". Nor were the designers tasked with identifying the hazardous factors associated with flammable gases potentially flowing back into the reclaimed water plant through the overflow pipes. They bear direct leadership responsibility for the occurrence of this accident. In accordance with the “Regulations on Rewards and Punishments for Employees of China Chengda Engineering Co., Ltd.”, the employment contract shall be terminated as a disciplinary measure. (3) Gu Xiulian, the reviewer of the design drawings for the BDO project at China Chengda Engineering Co., Ltd., is responsible for reviewing all aspects of the design process, including design verification, design confirmation, and design changes. She bears primary responsibility for addressing major technical issues as well as ensuring that the design solutions are correct and reasonable. They violated the requirements set out in the company’s \"Work Standards\" regarding the verification that finished designs comply with relevant standards, specifications, and unified engineering regulations. They failed to promptly identify and correct the issue of designers not including sealing devices such as water seals on the 6 overflow pipes or the main pipe through which these overflow pipes connect, and are thus held fully responsible for the occurrence of this accident. In accordance with the “Regulations on Rewards and Punishments for Employees of China Chengda Engineering Co., Ltd.”, the employment contract shall be terminated as a disciplinary measure. (4) Mao Ping from China Chengda Engineering Co., Ltd., the BDO project design drawing reviewer, is responsible for reviewing various aspects of the design process such as design verification, design confirmation, and design changes, and is accountable for the quality of the design documents that she reviews. They violated the requirements set out in the company’s \"Work Standards\" regarding whether the design complies with relevant standards, specifications, and uniform engineering regulations. They failed to provide any feedback regarding the fact that the designers did not include sealing devices such as water seals on the 6 overflow pipes or the main pipe through which these pipes converge, and are therefore held fully responsible for the occurrence of this accident. In accordance with Article 44 of the Measures for Punishing Illegal Acts in Work Safety, a fine of 5,000 yuan is imposed on them ； A severe reprimand is imposed in accordance with the Employee Reward and Punishment System of China Chengda Engineering Co., Ltd. (5) Jin Qinglin, the person in charge of the process design for recycled water use in the BDO project at China Chengda Engineering Co., Ltd., is responsible for the design progress and quality of this project. When determining the design scheme for changing the route of the overflow pipes, no identification of hazardous factors was carried out, and during the discussions in the special meeting, there was no proposal to install blocking devices such as water seals on the 6 overflow pipes or on the main pipe that collects them ； No design change order was issued, resulting in discrepancies between the construction drawings for the reclaimed water treatment process and the floor plans of the underground pipelines. Asholding significant responsibility for the occurrence of this accident, in accordance with Article 44 of the Measures for Punishing Illegal Acts in Work Safety, a fine of 5,000 yuan is imposed on them ； A reprimand is imposed in accordance with the Employee Reward and Punishment System of China Chengda Engineering Co., Ltd. (6) Lei Yongsong, the on-site manager for the BDO project at China Chengda Engineering Co., Ltd., is responsible for all on-site work within the scope of the contract, as well as for managing and coordinating the subcontractors at the project site. When the project manager is away, he acts as the project manager and carries out his duties. The potential risk of failing to effectively isolate the water reuse plant and the underground sewage main, which were under construction, was not identified in a timely manner; an approval signature was placed on the intermediate handover certificate without the water seal well having been completed and without effective safety measures in place, indicating inadequate management of the project’s subcontractors. Asholding significant leadership responsibility for the occurrence of this accident, in accordance with Article 44 of the Measures for Punishing Illegal Acts in Work Safety, a fine of 5,000 yuan is imposed on them ； A warning penalty is imposed in accordance with the Employee Reward and Punishment System of China Chengda Engineering Co., Ltd. (7) Li Yangping, the BDO project design manager at China Chengda Engineering Co., Ltd., was responsible for organizing and coordinating the design and technical aspects of the project, as well as ensuring that the design progress met the required quality standards. He failed to fulfill his duties in terms of design and technical management; he did not properly oversee the change in the routing of the overflow pipes from the rainwater system to the sewage system. He also failed to identify potential hazards, and did not promptly detect or correct the issue of the designers failing to include water seals or other protective devices at the 6 overflow pipes or the main collection pipes. Asholding significant leadership responsibility for the occurrence of this accident, in accordance with Article 44 of the Measures for Punishing Illegal Acts in Work Safety, a fine of 5,000 yuan is imposed on them. (8) Xu Gang, the BDO project manager of China Chengda Engineering Co., Ltd., is the primary person responsible for safety production at this project site. He was negligent in terms of design management, quality management, and safety management for the general contracting project, and failed to ensure adequate safety management by the construction units. When modifying the design of the overflow pipeline route, blocking devices such as water seals were not included ； The quality inspection procedures for verifying the documents and on-site conditions of concealed works such as water seal wells were not properly followed during the interconnection of underground sewage networks ； The project team and construction unit fail to carry out work handover procedures when there are staff changes ； The failure to promptly identify and rectify issues and potential hazards, such as the lack of effective barriers between the under-construction reclaimed water plant and the underground sewage main, makes them primarily responsible for this incident. In accordance with Article 44 of the Measures for Punishing Violations of Work Safety Regulations, a fine of 9,000 yuan was imposed on them. (9) Cao Guang, legal representative of China Chengda Engineering Co., Ltd., as the primary person in charge of the company, failed to ensure proper implementation of safety management, quality management, design management, and construction management within the project department. He neglected to supervise and manage the issues and potential hazards related to his responsibilities as the general contractor. Therefore, he bears significant leadership responsibility for the occurrence of this accident. In accordance with the provisions of Item 2, Article 38 of the Regulations on the Reporting, Investigation and Handling of Production Safety Accidents, Cao Guang shall be subject to an administrative penalty equivalent to 40% of his previous year’s annual income (251,945 yuan), which amounts to a fine of 100,778 yuan. 2. China National Ninth Chemical Engineering Construction Company: (1) Liu Lian, the head of the BDO project’s engineering management department at China National Ninth Chemical Engineering Construction Company, is responsible for overseeing the construction quality and the progress of work on site. During the construction of the water seal wells in the facility, relevant provisions of the Regulations on Quality Management of Construction Projects were violated. Without obtaining the required tee fittings for the water seals and before completing the construction in accordance with the plans, no written reports were submitted, and no reliable safety measures such as barriers or warning signs were put in place. Proper work handover procedures and technical briefings were not carried out either. Moreover, the filling in of the water seal wells located on the main sewage pipes was not detected or stopped in time, thereby creating potential hazards that could lead to accidents. They bear significant responsibility for the occurrence of this accident. Dismissal is imposed in accordance with the Employee Reward and Punishment System of China Chemical Engineering Ninth Construction Company. (2) Zhang Zhenjiang, the construction manager for the BDO project at China National Chemical Engineering Corporation’s Ninth Construction Company, was responsible for managing the construction progress, safety, and quality on site. In violation of the relevant provisions of the Regulations on Quality Management of Construction Projects, he covered the water seal well with construction panels without completing the construction in accordance with the design requirements, nor implementing any safety measures to isolate or seal the pipes inside the well; furthermore, no warning signs or barriers were set up ； The filling of the water seal well was not detected or stopped in a timely manner. Asholding significant leadership responsibility for the occurrence of this accident, in accordance with Article 44 of the Measures for Punishing Illegal Acts in Work Safety, a fine of 5,000 yuan is imposed on them. (3) Tian Hongsheng, the BDO project manager at China National Chemical Engineering Ninth Construction Company, as the primary person responsible for safety in the project team, failed to ensure proper management of construction, quality control, and safety measures within the project team. In violation of the relevant provisions of the Regulations on the Quality Management of Construction Projects, the construction boards were used to cover the water seal well before it was constructed in full accordance with the drawings. No safety measures such as isolation or sealing of the pipes inside the well were implemented. No warning signs or fences were set up. The documentation and on-site inspections pertaining to the water seal well were not carried out; nevertheless, signatures were affixed on the interim handover certificate for acceptance. Consequently, the subsequent backfilling of the water seal well and its commissioning for trial operation went undetected and unabated ； He bears primary leadership responsibility for the occurrence of this accident, due to his failure to exercise proper supervision and management over issues such as the frequent reassignment of personnel in the project team, the inadequate fulfillment of work handover procedures, and the failure to inform the general contractor accordingly. In accordance with Article 44 of the Measures for Punishing Violations of Work Safety Regulations, a fine of 9,000 yuan was imposed on them. (4) Xu Jian, General Manager of China Chemical Engineering Ninth Construction Company, as the primary person responsible for work safety, failed to promptly identify and rectify issues related to construction management, quality management, and safety management within the project department. He also lacked effective supervision; thus, he bears significant leadership responsibility for the occurrence of this accident. In accordance with the provisions of Item 2, Article 38 of the Regulations on the Reporting, Investigation and Handling of Production Safety Accidents, Xu Jian was subject to an administrative penalty equivalent to 40% of his previous year’s annual income (78,000 yuan); thus, a fine of 31,200 yuan was imposed. 3. Liu Ronggao, the BDO project manager at China Chemical Engineering Sixteenth Construction Co., Ltd., serves as the primary person responsible for work safety within the project team. He is fully in charge of the management of the project department. In violation of the relevant provisions of the Regulations on the Quality Management of Construction Projects, as a professional company specializing in the installation of chemical and petroleum equipment and pipelines, it failed to raise any objections regarding the discrepancy between the construction drawings for the reclaimed water process and the layout plan of underground pipelines ； After the six overflow pipes from the construction were connected to the manhole, no blocking or cutoff devices were installed; this constitutes a major leadership responsibility for the occurrence of this accident. In accordance with Article 44 of the Measures for Punishing Violations of Work Safety Regulations, a fine of 9,000 yuan was imposed on them. 4. Inner Mongolia Collin Construction Project Supervision Co., Ltd. (1) Feng Jun, the professional supervision engineer for underground pipeline systems in the BDO project at Inner Mongolia Collin Construction Project Supervision Co., Ltd., is responsible for overseeing the HVAC systems as well as the ventilation systems in the control center and R&D center. There were violations of the relevant provisions in the “Code for Construction Project Supervision”. Supervision over concealed works such as water seal wells was inadequate. The acceptance procedures for the water seal wells constructed by Jiuhua Construction were not strictly carried out; moreover, the fact that these water seal wells were put into normal use before completion went undetected and uncorrected. They bear significant responsibility for this incident. In accordance with Article 44 of the “Measures for Punishing Violations of Work Safety Regulations”, they are fined 5,000 yuan. It is recommended that they be removed from their supervisory position. (2) Tian Dong, the chief supervision engineer for the BDO project at Inner Mongolia Kelin Construction Project Supervision Co., Ltd., serves as the primary person responsible for work safety in the project department and is fully in charge of all operations of the supervision project team. By violating the relevant provisions of the \"Code for Supervision of Construction Projects,\" failing to properly fulfill the duties of the chief supervisor regarding concealed works, allowing concealed elements such as water seal wells that had not been constructed in accordance with the design specifications to be put into use without implementing proper sealing or isolation measures, and failing to properly carry out the procedures for reviewing submitted documents, he bore significant leadership responsibility for the occurrence of this accident. In accordance with Article 44 of the Measures for Punishing Illegal Acts in Work Safety, a fine of 9,000 yuan is imposed on them; it is recommended to impose a warning penalty in line with the Supervision Staff Management System of Inner Mongolia Collin Construction Project Supervision Co., Ltd. (3) Tian Maolin, General Manager of Inner Mongolia Collin Construction Project Supervision Co., Ltd., as the primary person in charge of Collin Supervision, failed to address issues and potential risks such as the failure to follow strict procedures for submitting and reviewing documents in the supervision work carried out by the company’s BDO supervision team regarding concealed works. He failed to detect and prevent these problems in a timely manner, and lacked effective oversight and control over the supervisors’ failure to fulfill their duties properly; he thus bears primary leadership responsibility for the occurrence of this accident. In accordance with Article 38, Item 2 of the Regulations on the Reporting, Investigation, and Handling of Production Safety Accidents, Tian Maolin was subjected to an administrative penalty of 40% of his annual income from the previous year (72,000 yuan), resulting in a fine of 28,800 yuan. 5. Beijing Zhongheng Xinda Engineering Project Co., Ltd. (1) Gao Dongping, the professional supervision engineer at Beijing Zhongheng Xinda Engineering Project Co., Ltd., was responsible for overseeing aspects related to the BDO equipment and its processes. He violated the relevant provisions of the \"Code for Construction Project Supervision\" by failing to submit any written supervision opinions regarding the change in the route of the 6 overflow pipelines in the recycled water workshop from the rainwater system to the sewage system. They bear significant responsibility for this incident. In accordance with Article 44 of the “Measures for Punishing Violations of Work Safety Regulations”, they are fined 5,000 yuan. It is recommended that they be removed from their supervisory position. (2) Zhu Zhongye, the director of the BDO project department at Beijing Zhongheng Xinda Engineering Project Co., Ltd., is fully responsible for all activities of the supervision department; he held the position of project director without possessing the qualifications of a **registered supervision engineer ； No objections were raised regarding the discrepancy between the construction drawings for the reclaimed water treatment process and the layout plans of the underground pipelines. It was not detected in time that there were no check valves or other devices to prevent backflow in the 6 overflow pipes in the reclaimed water treatment plant, nor in the main pipe that collects these overflow pipes. No effective isolation and safety measures were implemented for the reclaimed water treatment plant, which was under construction, and for the sewage pipeline network that had already started trial operation; supervision was inadequate. By failing to raise any objections to the commencement of trial production, carrying out the handover procedures, and signing the handover certificate, they bear significant leadership responsibility for the occurrence of this accident. In accordance with Article 44 of the Measures for Punishing Illegal Acts in Work Safety, a fine of 9,000 yuan shall be imposed on them; it is recommended that the company dismiss them. (3) Wang Zhigang, the deputy general manager of Beijing Zhongheng Xinda Engineering Project Co., Ltd. (and the person in charge of the Inner Mongolia office), is responsible for supervision work within Inner Mongolia, and bears primary responsibility for Zhu Zhongye, who does not possess the qualifications of a registered supervision engineer, holding the position of project director ； There was inadequate supervision and management of the BDO project department in fulfilling its duties, and significant leadership responsibility lies with them for the occurrence of this accident. In accordance with Article 44 of the Measures for Punishing Violations of Work Safety Regulations, a fine of 9,000 yuan was imposed on them. 6. Inner Mongolia Dongyuan Technology Co., Ltd. (1) Huang Baosen, the head of the Engineering Department at Inner Mongolia Dongyuan Technology Co., Ltd., was responsible for coordinating water, electricity, and gas supply in construction projects. He failed to comply strictly with the relevant provisions of the \"Regulations on Quality Management of Construction Projects\"; he did not properly carry out the procedures for reviewing documents and inspecting the quality of hidden elements such as underground pipelines and water seal wells. Despite the fact that these water seal wells were not ready for normal use, he signed the handover certificate in violation of regulations. As the party bearing significant responsibility for the occurrence of this accident, in accordance with Article 44 of the Measures for Punishing Illegal Acts in Work Safety, a fine of 5,000 yuan is imposed on them. (2) Zhu Qinghe, the deputy general manager of Inner Mongolia Dongyuan Technology Co., Ltd., as the deputy commander of the project under construction, was responsible for the actual progress of the project. He failed to adequately supervise and manage issues related to design, construction, safety, and quality control on the part of the general contractor and the supervision unit. He also failed to detect in time the potential risks associated with the lack of effective separation measures between the wastewater treatment plant that was under construction and the underground sewage pipelines that had already started operating, and thus bears significant leadership responsibility for the occurrence of this accident. In accordance with Article 44 of the Measures for Punishing Illegal Acts in Work Safety, a fine of 5,000 yuan is imposed on them. (3) Yang Dong, the principal person in charge of Inner Mongolia Dongyuan Technology Co., Ltd., as the overall commander of the projects under construction and those in trial production, failed to adequately supervise and manage issues such as inadequate design management, construction management, safety management, and project quality control on the part of the general contractor and supervision units; he thus bears significant leadership responsibility for the occurrence of this accident. In accordance with Article 38, Item 2 of the Regulations on the Reporting, Investigation, and Handling of Production Safety Accidents, Yang Dong was subjected to an administrative penalty of 40% of his annual income from the previous year (164,352 yuan), resulting in a fine of 65,741 yuan. 7. Inner Mongolia Autonomous Region Petroleum and Chemical Engineering Construction Quality Supervision Station: This station is responsible for examining the qualifications of the construction and supervision units as well as the personnel involved in the Dongyuan Technology BDO project, as well as ensuring that the project contracts comply with relevant regulations. The supervision over the lack of **qualified registration as a supervision engineer among the managers of BDO’s project department at Beijing Zhongheng Xinda Supervision Company was inadequate. It is recommended that the Petroleum and Chemical Engineering Construction Quality Supervision Station of Inner Mongolia Autonomous Region impose administrative sanctions on the relevant responsible persons within this company in accordance with relevant regulations, and send a copy of the outcomes of such actions to the Wuhai City Safety Committee Office. 8. Wuda District ** (1) Liu Huirong, Deputy Director of the Wuda District Industrial Park Management Committee, at the deputy department level; responsible for work related to work safety, and bears leadership responsibility for this accident. It is recommended that the Municipal Supervision Bureau impose an administrative warning on him. (2) Li Jinzhu, Deputy Director and Chief Engineer of the Uda District Housing and Construction Bureau, at the section-level position, is responsible for work related to work safety; he bears leadership responsibility for this accident. It is recommended that the People’s Court of Uda District impose an administrative warning on him. (II) Units recommended for administrative penalties
1. Liability handling of enterprises
(1) China Chengda Engineering Co., Ltd. failed to duly fulfill its responsibilities regarding the safety management of subcontractors, in accordance with the general contracting contract for design, procurement, and construction of the 100,000-ton-per-year BDO project. Technical and design management was inadequate; the relevant provisions of the \"Code for Fire Protection Design of Petrochemical Enterprises\" were not strictly followed, and barrier devices such as water seals were not installed at the 6 overflow pipes or the main collection pipes ； The process flow diagram of the reclaimed water treatment system does not match the plan view of the underground pipelines ； No effective isolation measures were taken for the sewage main put into trial production and the wastewater reuse plant under construction. In violation of the relevant provisions of the Regulations on Quality Management of Construction Projects, proper on-site inspection duties were not fulfilled during the intermediate handover of the plant’s underground pipeline network for the BDO project; hidden works such as water seal wells were not completed in accordance with the design specifications before being filled in, yet the intermediate handover procedures were carried out, and approval was given for the BDO project to start trial production. The safety supervision over subcontractors was inadequate. There was frequent personnel turnover in the BDO project department and at Jiuhua Construction; consequently, procedures regarding work handovers, record-keeping, and technical briefings were not carried out properly as required. In accordance with the provisions of Item 2, Article 37 of the Regulations on the Reporting, Investigation and Handling of Production Safety Accidents, a administrative penalty of 230,000 yuan was imposed on China Chengda Engineering Co., Ltd. (2) China National Chemical Engineering Ninth Construction Company violated the relevant provisions of the Regulations on Quality Management of Construction Projects; it covered the water seal well with construction panels without completing the construction in accordance with the design, without implementing any safety measures such as partitions or seals, and without setting up any warnings or barriers ； The intermediate handover procedures were carried out without conducting the necessary verification of documents and on-site conditions for the water seal well, and the fact that the water seal well had been filled in was not detected or stopped in a timely manner ； No objections were raised to the start of trial production for the BDO project ； There were frequent staff transfers; the work handover procedures were not properly followed, and the general contractor was not informed accordingly. In accordance with Article 37, Item 2 of the Regulations on the Reporting, Investigation, and Handling of Production Safety Accidents, a fine of 220,000 yuan was imposed on China Chemical Engineering Ninth Construction Company. (3) China Chemical Engineering 16th Construction Company violated the relevant provisions of the Regulations on Quality Management of Construction Projects; as a company specialized in the installation of chemical and petroleum equipment and pipelines, it failed to raise any objections regarding the discrepancy between the construction drawings for the reclaimed water system and the layout plans for underground pipelines. After the 6 overflow pipes were combined and connected to the manhole for construction, no barrier or shut-off device was considered for installation prior to the facility’s commissioning. In accordance with Article 37, Item 2 of the Regulations on the Reporting, Investigation, and Handling of Production Safety Accidents, a fine of 210,000 yuan was imposed on China Chemical Engineering 16th Construction Company. (4) Inner Mongolia Collin Construction Project Supervision Co., Ltd. violated the relevant provisions of the \"Construction Project Supervision Standards\" by failing to provide proper supervision over concealed works such as water seal wells; it failed to detect in a timely manner that Jiuhua Jian did not construct the water seal wells in accordance with the design specifications and filled them in before completion. Failing to properly supervise the failure to follow proper work handover procedures for the personnel transfers at Jiuhua Construction. In accordance with Article 37, Item 2 of the Regulations on the Reporting, Investigation, and Handling of Production Safety Accidents, an administrative penalty of 210,000 yuan was imposed on Inner Mongolia Colin Construction Project Supervision Co., Ltd. (5) Beijing Zhongheng Xinda Engineering Project Co., Ltd. violated the relevant provisions of the \"Code for Construction Project Supervision\" by appointing Zhu Zhongye, who does not possess the qualifications of a registered supervision engineer, as the project director for the BDO project ； As a professional supervision company, it failed to issue any supervision comments regarding the discrepancy between the construction drawings for the recycled water system and the layout plans of the underground pipelines ； The 6 overflow pipes in the recycled water plant were not detected in time, nor were any backflow prevention devices such as water seals installed on the main pipe that collects these overflow pipes ； No effective barrier safety measures were implemented for the wastewater reuse plant that was under construction and installation, nor for the sewage pipeline network that had started trial operation; supervision was inadequate. No objections were raised regarding the start of trial production. In accordance with Article 37, Item 2 of the Regulations on the Reporting, Investigation, and Handling of Production Safety Accidents, a fine of 210,000 yuan was imposed on Beijing Zhongheng Xinda Engineering Project Co., Ltd. 2. Handling of territorial supervision responsibilities: In accordance with the principle of territorial management, the People’s Government of Wuda District is responsible for overseeing this enterprise; the failure to fulfill these supervision duties led to the occurrence of this accident. Uda District is ordered to conduct a thorough self-examination before the city’s people, carefully summarize and learn from the lessons of this accident, further strengthen and improve the supervision of work safety in industrial construction projects, and effectively prevent similar accidents from occurring. The above fines shall be enforced in accordance with the law by the Wuhai City Work Safety Supervision Bureau. VI. Preventive Measures and Recommendations (1) The general contractor shall, in accordance with the EPC contract, earnestly fulfill its responsibilities for safety management in construction. First, immediately organize the construction units and supervision units, and hire experts to conduct a thorough and comprehensive inspection of all installations within the plant, in accordance with standards such as the \"Code for Fire Protection Design of Petrochemical Enterprises\" and the \"Code for Fire Protection Design of Building Engineering\", as well as other industry technical specifications. Special attention should be paid to key installations and critical areas such as the sewage system, plant equipment, underground pipelines, concealed works, electrical equipment, and fire protection facilities. Any identified hazards and problems should be recorded in detail, and corrective actions should be taken strictly in accordance with the \"five fixed principles\". In accordance with the requirements of the \"Notice on Further Strengthening the Safety Design Management of Chemical Construction Projects\" (No. An Jian Zong Guan San 76), experts in design, production management, process engineering, safety, equipment, electrical systems, instrumentation, and environmental protection were organized to conduct HAZOP analyses on the design, equipment, and project quality of the BDO project. Based on the results of these analyses, corrective actions and recommendations were formulated, and thorough improvements were carried out. Secondly, it is necessary to strengthen supervision and management in areas such as design, construction, quality, and safety. Construction companies should be urged to fulfill their primary responsibilities regarding safe production; the implementation of safety responsibility systems must be enhanced. Systems for identifying risks associated with construction that does not comply with standards, as well as changes to designs, need to be improved. Supervision during the construction process should be intensified, and appropriate safety measures must be put in place. In particular, plans for ensuring the proper construction, quality control, and safety measures for concealed works are essential. There should be isolation devices for substances such as water, gas, and liquids between key equipment units and buildings. Effective isolation measures must also be implemented between production equipment and the buildings used for construction. Third, it is necessary to implement safety production management systems such as personnel safety training and risk control, strictly supervise and review the qualifications of construction units and their management staff, and resolutely eliminate any gaps in site management. (2) The design unit must strictly review the design plans, process requirements, and safety facilities in accordance with standards and regulations such as the \"Code for Fire Protection Design of Petrochemical Enterprises\", the \"Guidelines for Safety Design Management of Chemical Construction Projects\" (AQ/T3033), and the \"Notice on Further Strengthening the Safety Design Management of **Chemical Construction Projects\". It is necessary to conduct a thorough assessment and detailed identification of existing risks, as well as a recheck of the quality of the safety design, with particular attention paid to the safety facilities involved in the safety relief systems and the gas, liquid, material, and wastewater discharge systems. To strengthen the management of design changes and strictly enforce the relevant systems for such changes, it is necessary to carry out risk identification and analysis procedures, and the changes must be approved by the relevant management and technical supervisors as well as confirmed by the supervision unit. For sewage discharge pipes, a water seal and a harmful gas emission system in the form of manholes must be installed in strict accordance with the \"Code for Fire Protection Design of Petrochemical Enterprises\". Gas detectors and alarms should be added in areas where there is a risk of flammable gas leaks, and ventilation facilities should be installed in enclosed factories. (3) The construction unit must thoroughly implement the newly revised Work Safety Law, and in strict accordance with relevant laws and regulations such as the Regulations on Work Safety Management in Construction Projects and the Regulations on Quality Management of Construction Projects, it must earnestly fulfill its primary responsibilities as an enterprise. Establish and improve various safety production management systems with the safety production responsibility system as their core, and assign safety production responsibilities at each level to the construction workers. Strengthen technical management and safety risk control at construction sites, strictly implement the permit system for hazardous operations, carefully assess and identify risks associated with these operations, and establish practical preventive measures. It is necessary to strictly enforce the technical and quality requirements as well as safety measures for the construction of projects with high risks, such as underground works, concealed works, and formwork installation. For projects that have not been completed in accordance with the design specifications or have not passed inspection, effective preventive or isolation measures must be taken to avoid industrial safety accidents. Implement strict project management by further clarifying the safety production responsibilities of the project manager, technical supervisor, construction supervisor, as well as safety officers and quality inspectors. Organize training sessions on the mandatory standards set out in the Petrochemical Regulations to ensure that these standards are properly implemented, in line with the qualification levels of first-class petrochemical construction companies. (IV) The supervision unit shall, in accordance with the \"Code for Supervision of Construction Projects\", the \"Regulations on Work Safety Management in Construction Projects\", and the \"Regulations on Quality Management of Construction Projects\", fully assume its primary responsibility for work safety, and firmly uphold the principle that \"safe management is an essential part of project management\". Thoroughly review construction design drawings, technical plans, schedules, as well as the qualifications of the construction and subcontracting units. Implement strict design change management, include design changes within the scope of supervision work, and construction shall not be commenced without the approval of the supervisor. Strict supervision and quality control must be exercised over high-risk construction activities such as concealed works and formwork installation. Construction shall not be initiated without prior risk identification, expert evaluation, and approval of the safety technical measures. The chief supervision engineer of the supervision unit must hold a qualification as a registered supervision engineer to take up the position. (5) The construction unit must immediately halt trial production, earnestly implement corrective measures, and only after completing the acceptance procedures in strict accordance with the requirements of the Autonomous Region Work Safety Supervision Bureau may it resume production. Relevant expert technicians in organization, design, construction, supervision, quality, and safety were assembled to conduct a comprehensive inspection for potential hazards in the production, storage, and transportation facilities, equipment, towers, and safety devices related to the BDO project and the calcium carbide project. Any identified hazards were rectified thoroughly in strict accordance with the “five determinates” principle. Strengthen supervision over the acceptance of engineering projects and ensure strict quality control at the project acceptance stage. Establish and improve a responsibility system for quality inspection of key installations and critical areas, including concealed works, underground structures, sewage systems, plant equipment, electrical equipment, and fire protection facilities, and further clarify the responsible parties. Strict supervision and management must be exercised to ensure that there are isolation and shutdown devices for media such as water, gas, and liquids between the buildings housing key equipment; effective isolation measures must also be in place for both production equipment and the buildings used for construction. It is imperative to prevent the deployment into use of any equipment or facilities that have not been completed, for which the necessary change approval procedures have not been followed, or that have not undergone risk identification and assessment. In accordance with the contract, it is necessary to implement the four technical preventive measures proposed by the expert group in the “Technical Appraisal Report on the ‘October 7’ Major Production Safety Accident at the Recycled Water Plant Contracted by China Chengda Engineering Co., Ltd.”: reliable real-time monitoring systems should be installed for key equipment and critical areas, as well as for the wastewater treatment system ； Facilities to prevent backflow of combustible gases in the sewage main must be added ； Ensure that the existing water seal devices in the equipment are functioning properly to prevent gas leakage ； Enhance monitoring and ventilation in wastewater treatment facilities to prevent the accumulation of flammable gases and toxic, harmful gases. (6) In the event of changes among the various participating units and personnel from the project owner, proper handover procedures must be followed. Systems such as a \"Personnel Transfer Handover Management System\" and a \"Personnel Transfer Handover Form\" should be established, with designated persons for handing over tasks, receiving them, and overseeing the process, so as to make such handovers more systematic, standardized, and institutionalized. It is necessary to organize principal responsible persons, professional supervisors, engineering and technical personnel, and safety managers to conduct centralized study of technical specifications such as the “Petrochemical Regulations”. Various mandatory standards must be effectively incorporated into the assessment and control of work safety risks for their respective units and projects. Construction management, quality management, and safety management should also be made key components of the supervision work. (7) The Housing and Urban-Rural Development Bureau of Wuda District must earnestly fulfill its supervisory responsibilities regarding industrial construction projects within its jurisdiction. In accordance with the principle of “three mandatory areas of supervision,” it should proactively communicate and coordinate with the Petrochemical Supervision Station to clarify its responsibilities regarding the safety supervision of chemical construction projects ； In accordance with the requirements of regulatory tasks, efforts should be made promptly to develop regulatory personnel, equipment, and methods that are suitable for those tasks, in order to ensure comprehensive and thorough supervision of all types of industrial construction projects and to prevent the occurrence of various accidents. (VIII) The Petrochemical Supervision Station must proactively communicate with local construction administrative authorities. While overseeing the quality of petrochemical project construction, it must also implement safety supervision responsibilities at all levels. It is necessary to strictly adhere to the principle stated in the directives that \"those who are in charge of an industry must also be responsible for ensuring safety, and those who are in charge of certain operations must also ensure safety.\" It is essential to fulfill the responsibility of ensuring safety alongside the management of construction quality, and to fully leverage the functions of professional quality supervision in petrochemical projects. In strict accordance with relevant laws and regulations such as the “Regulations on Quality Management of Construction Projects” and the “Regulations on Work Safety Management in Construction Projects”, as well as industry-related standards like the “Code for Fire Protection Design of Petrochemical Enterprises”, we provide comprehensive quality supervision throughout the entire process of new construction, renovation, and expansion projects undertaken by chemical enterprises. Special emphasis is placed on supervising safety facilities that are crucial to the safety of people’s lives and property. In accordance with the \"Rules and Procedures for Quality Supervision of Petroleum and Chemical Engineering Projects by the Inner Mongolia Petroleum and Chemical Engineering Project Quality Supervision Station\", regular and phased inspections shall be carried out based on the progress of the projects under supervision. These inspections should combine on-site checks with random reviews of documents; particular attention should be paid to those processes that may pose serious quality risks or affect the safe operation of the project, as well as to concealed works, critical structures, and key areas and facilities with significant issues. Random checks should also be conducted on the original documents related to various inspections and acceptance procedures, to ensure that they are standardized, accurate, and reflect the actual quality status of the project, as well as on the major construction materials used. (IX) The people of Wuda District must earnestly draw lessons from the tragic explosion that occurred on October 7th at the recycled water plant constructed under the general contracting of China Chengda Engineering Co., Ltd., and firmly adhere to the principle that development must never come at the cost of human lives. Properly handle the relationships between safety and development, safety and production, as well as safety and efficiency, and improve and refine the work safety responsibility system characterized by \"shared responsibilities for the Party and government, dual responsibilities for each position, and joint oversight.\" Further strengthen the comprehensive supervision and management of work safety in industrial construction projects within this administrative region, earnestly fulfill local management responsibilities, further refine the safety supervision duties for industrial construction projects, and ensure that there are no gaps in the safety supervision of such projects, with full coverage. Immediate warning education sessions on work safety for industrial construction projects and industrial enterprises should be held throughout the region, so as to achieve the goal of using each accident as a warning to all other enterprises; the new Work Safety Law must be thoroughly implemented, and design, construction, supervision, and related regulatory agencies must be urged to fully assume their responsibilities regarding work safety. Accident Investigation Team, April 23, 2015