The “9·14” explosion and fire accident at Liaoning Fushun Shunte Chemical Co., Ltd. (Case analysis)

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I. Accident investigation and analysis (1) Summary of the accident 1. Brief description of the accident At around 10:10 on September 14, 2013, an explosion and fire occurred at Fushun Shunte Chemical Co., Ltd. (hereinafter referred to as Shunte Company). The accident resulted in 5 deaths, the destruction of two storage tanks, and the complete combustion of 50 m3 of trimethyl orthoformate product, causing direct economic losses of 1.2 million yuan. 2. Cause analysis
(1) Direct cause
Sparks generated by unauthorized electric welding operations performed by Shunte workers on the top of the tank ignited the trimethyl ester vapor leaking from the sampling port on the tank roof. The flames then traveled back into the tank, causing an explosion of the explosive gases inside. This is the direct cause of the explosion and fire accident. (2) Indirect causes: ① Shunt Company lacked a sense of responsibility regarding safe production; it carried out illegal construction and production without having the safety facilities for the newly built installations reviewed first ； ②Shunte Company has poor safety management and a weak awareness of risks. No construction plan or scheme was developed for this renovation project, no thorough analysis of hazardous factors was carried out, and there was a lack of inspections at the work site; as a result, the sources of trimethyl ester vapor in the hot work area were not isolated. ③There are problems with the method of altering the pipeline layout (the way of working). It would have been possible to pre-make pipe fittings with flanges and then join them using those flanges, but instead, the most risky option was chosen: welding on top of the tank. ④Responsibilities regarding work safety are not being fulfilled. Although the enterprise has established a safety production responsibility system as well as various internal management systems and safety operating procedures, these are not properly implemented. The management and operational staff lack a strong safety awareness; they fail to strictly implement the change management system and the permit system for hot work, resulting in illegal operations. When there were hazardous materials inside the tank, no flammable gas analysis was conducted in the area at a distance of not less than 10 meters from the welding site as required, nor was a work permit for special welding operations issued; instead, a temporary electricity use permit was issued in violation of regulations. ⑤The relevant operating procedures were not gradually improved and revised as required. The absence of procedures for sampling from the top of the tank meant that the originally sealed blind flange at the sampling port lost its ability to prevent trimethyl ether vapor from escaping, creating a serious risk of accidents. There is a lack of management regarding the tank top sampling ports that are rarely used. Although the tightness of other flanges has been checked during routine inspections, no inspections have ever been conducted on the bolt tightness of the blind flanges at the tank top sampling ports or on the condition of their gaskets. ⑥There are gaps in the safety training and assessment for new workers. Although the newly hired welders possess operation certificates, the company has no records of any safety training provided to them, and they started working without going through any assessments. ⑦Intermediary agencies fail to exercise strict oversight during corporate standardization evaluations, and do not fully fulfill their responsibility to serve enterprises and ensure quality control. During the evaluation of Shunte’s work safety standardization in October 2012, it was found that there were significant shortcomings in the company’s daily construction management: no plans had been formulated, and hazard identification had not been carried out properly. As a result, all 10 points possible were deducted; this was the only item for which full points were lost. However, this issue was not listed separately when summarizing the main problems, thus failing to draw the company’s serious attention and prompt corrective actions. Additionally, it did not provide safety regulatory authorities with any targeted areas for supervision ； During the evaluation, illegal construction activities by the enterprise were detected; it was also known that the said facility was still in the approval phase and should not yet be constructed. Yet, on the grounds that it had not started operations, the full 100 points allocated for this criterion were not deducted as required, resulting in the enterprise’s overall score meeting the requirements for level 3 standardization. ⑧The safety supervision work by the Safety Supervision Bureau in Dongzhou District, Fushun City is inadequate. The Safety Supervision Bureau of Dongzhou District is responsible for the daily supervision and management of safety production at Shunte Company. During its routine inspections of this company, it failed to fulfill its duties properly and did not effectively prevent the company from engaging in illegal construction and production activities. (II) Basic Information 1. Information on the units involved in the accident: Shunt Company is a private enterprise founded on April 26, 2002. Its address is No. 52, Chengxiang Road, Dongzhou District, Fushun City. The legal representative is Mr. Tian, and the company currently has 60 employees on staff. The company is a manufacturer of hazardous chemicals, and its safety production license number is (Liao) WH Safety License No. 0169; the validity period of this license ranges from January 6, 2012, to January 5, 2015. The permitted substances include: triethyl orthoformate (hereinafter referred to as triethyl ester), phosphorous acid, hydrochloric acid, chloroethane, ethyl formate, trimethyl orthoformate (hereinafter referred to as trimethyl ester), and methyl formate. Triethyl ester and trimethyl ester are the main products, with an annual production of 2,000 tons each; the others are by-products and intermediates. At the time of certification, the main equipment and storage facilities consisted of 14 reactors with three reaction stages, a distillation unit (5 distillation columns, primarily used for separating and purifying triethyl ester), and 4 storage tanks for raw materials and products (with a total capacity of 320 m3). Batch production is adopted. 2. Basic information on the accident plant: Suntec Company uses a set of production plants to manufacture triethyl ester and trimethyl ester. To ensure product quality, since it was no longer feasible to use one distillation unit to separate and purify two products, a new distillation unit was installed at the end of August 2012 specifically for the separation and purification of trimethyl ester. The main equipment of the newly built distillation unit includes 5 distillation columns, a reflux tank below the columns, feed and product pumps, as well as the two product tanks that were involved in the accident. The tank numbers of the finished products are V041D (100 m3, hereinafter referred to as the large tank) and V041A (30 m3, hereinafter referred to as the small tank). The design calls for large tanks to store trimethyl ester and small tanks to store methyl formate, but in actual production, trimethyl ester is the one that is stored. The new facility received approval and registration from the Dongzhou District Development and Reform Bureau at the end of 2009. In October 2010, Fushun Chemical Industry Research and Design Institute carried out the construction drawing design for it. The construction contractor is Fushun Tiantong Construction Engineering Co., Ltd. Construction began on August 26, 2011, and the product tanks and the fire dike for the tank area were completed by the end of August 2012. Instrument installation was completed in September, enabling production conditions. From October to the end of December 2012, three trial production activities were carried out illegally, and illegal production continued from January 2013 until the time of the accident. On January 18, 2012, the Safety Supervision Bureau of Dongzhou District conducted an inspection and discovered that the company was carrying out illegal construction; it was verbally instructed to cease such illegal activities and to complete the necessary procedures related to the \"three simultaneities\" requirement. In August 2012, the enterprise submitted an application for a review of the safety conditions for the new facility. On September 19, 2012, the Fushun City Work Safety Supervision Bureau organized a meeting to assess those safety conditions, and issued an approval document regarding them in December 2012. At the same time, enterprises are informed that they should engage qualified design firms to carry out the design, and submit a separate document detailing the safety facility design for approval. On May 14, 2013, the Safety Supervision Bureau of Dongzhou District conducted a follow-up inspection of Shunte Company and found signs that the company had continued construction without submitting the design documents for safety facilities for approval. It ordered the company, in the form of an inspection report, to stop the illegal construction and complete the necessary procedures related to the principle of \"simultaneous design, construction, and operation\". In May 2013, Shuntai Company applied for an examination of the special document regarding the safety facilities design for this project. However, since this document did not meet the requirements set out in the new version of the \"Guidelines for Preparing Special Documents on Safety Facilities Design for Hazardous Chemicals Construction Projects\" issued by the State Administration of Work Safety (Document No. An Jian Zong Tang Guan San 39, effective as of April 7), the relevant materials were returned, and the application has not been submitted to date. (III) Sequence of accident occurrences: Date and time description. Shuntec plans to modify the small tank’s feed line, which is used to store the by-product methyl formate (produced in very small quantities) in the newly constructed distillation unit, so that it connects to the feed line of the large tank storing trimethyl ester; this will enable both tanks to store trimethyl ester. Before the renovation, temporary rerouting was carried out manually using hoses for connection. More than a month before the accident, workshop director Sun verbally proposed a renovation plan, but no written renovation plan or scheme was formulated. Prior to the incident, the maintenance workshop purchased valves and prefabricated relevant modification components, such as tees, for the feed line on the top of the large tank. The vertical branch of the tee serves as the feed line to the storage tank; there is a valve in place before the material enters the tank. On the horizontal end, one side is intended to be connected to the pipeline carrying the product from the temporary storage tank below the tower, while the other side is intended to be connected to a smaller tank ； A pipeline with a valve, intended to lead to a small tank, was pre-made (about 6 meters long). On September 14, the pumps and pipelines in the distillation workshop required maintenance, resulting in the shutdown of the distillation unit. At the regular work meeting chaired by Production Minister Kang at 7:30 on September 14, with General Manager Tian in attendance (Deputy Managers in charge of production and safety, Yu, and Safety Minister Jia were absent), Sun, the director of the distillation workshop, proposed carrying out pipeline modifications and requested that the construction be done on the same day. Tian said to be careful about safety and agreed to carry out the renovation project. After the meeting, Cui, the head of the maintenance workshop, assigned workers and established some basic safety measures; however, no construction plan was developed. Temporary electricity use permits were approved in violation of regulations, and special permits for hot work were not obtained as required. Subsequently, he left the factory (for reasons unrelated to work). At 8:30 on September 14, Sun, the director of the distillation workshop, led a team of six people—including Wang, the head of the maintenance crew; Li, the supervisor stationed below the tank; Shi, the welder; Bian, the maintenance worker; and Liu, the supervisor on top of the tank—to carry out work at the site. They used ropes to lift the welding machine and pre-made pipelines to the top of the large tank (by this time, the feed lines for both the large and small tanks had been cut). Li supervised the welding process from below the tank, while the other five people went up to the top of the tank to carry out their tasks. At 9:00 on September 14, electrician Sun arrived at the site, connected the power supply for the welding machine coming from the distribution panel on the south side of the tank area, and then left. Before starting the hot work, the personnel on the tank first installed asbestos blind plates behind the large tank’s feed valve and at the breather valve. However, no inspection was conducted on the tightness of the blind flange at the tank top gauging hole (sampling port), nor was an analysis of flammable gases in the working environment performed. At 10:10 on September 14, an explosion occurred in the large tank during the process of welding a tee joint to a prefabricated pipeline; the tank roof was thrown 15 meters away, and five people on the tank were crushed under it. The trimethyl ester inside the tank caught fire, resulting in a large blaze. Two minutes later, this fire ignited the smaller tank, which was located 1.65 meters away. Due to the small amount of trimethyl ester stored in the smaller tank, the flames died out shortly thereafter. The 50 m³ of trimethyl ester material inside the large tank burned out at around 18:00 under fire-fighting cover; both storage tanks were rendered unusable. (IV) Accident losses: The accident resulted in 5 deaths, the destruction of two storage tanks, and the complete combustion of 50 m3 of trimethyl orthoformate; the direct economic loss amounted to 1.2 million yuan. http://www.chemicalsafety.org.cn/uploads/161205/7-161205124554S3.jpg http://www.chemicalsafety.org.cn/uploads/allimg/161205/7-161205124613615.jpg http://www.chemicalsafety.org.cn/uploads/allimg/161205/7-16120512462BJ.jpg http://www.chemicalsafety.org.cn/uploads/161205/7-161205124642393.jpg Image: Accident scene (V) Analysis of accident causes 1. Analysis of direct causes The sparks generated by the workers at Shunt Company while performing welding work on the top of the tank ignited the methyl ester vapor that had leaked from the sampling holes on the tank’s roof; these sparks then spread inside the tank, causing an explosion of the explosive gases present there. This was the direct cause of the explosion and fire accident. 2. Analysis of indirect causes: ① Shunte Company lacked a sense of responsibility regarding safe production; it carried out illegal construction and production without having the safety facilities for the new installations reviewed first ； ②Shunte Company has poor safety management and a weak awareness of risks. No construction plan or scheme was developed for this renovation project, no thorough analysis of hazardous factors was carried out, and there was a lack of inspections at the work site; as a result, the sources of trimethyl ester vapor in the hot work area were not isolated. ③There are problems with the method of altering the pipeline layout (the way of working). It would have been possible to pre-make pipe fittings with flanges and then join them using those flanges, but instead, the most risky option was chosen: welding on top of the tank. ④Responsibilities regarding work safety are not being fulfilled. Although the enterprise has established a safety production responsibility system as well as various internal management systems and safety operating procedures, these are not properly implemented. The management and operational staff lack a strong safety awareness; they fail to strictly implement the change management system and the permit system for hot work, resulting in illegal operations. When there were hazardous materials inside the tank, no flammable gas analysis was conducted in the area at a distance of not less than 10 meters from the welding site as required, nor was a work permit for special welding operations issued; instead, a temporary electricity use permit was issued in violation of regulations. ⑤The relevant operating procedures were not gradually improved and revised as required. The absence of procedures for sampling from the top of the tank meant that the originally sealed blind flange at the sampling port lost its ability to prevent trimethyl ether vapor from escaping, creating a serious risk of accidents. There is a lack of management regarding the tank top sampling ports that are rarely used. Although the tightness of other flanges has been checked during routine inspections, no inspections have ever been conducted on the bolt tightness of the blind flanges at the tank top sampling ports or on the condition of their gaskets. ⑥There are gaps in the safety training and assessment for new workers. Although the newly hired welders possess operation certificates, the company has no records of any safety training provided to them, and they started working without going through any assessments. ⑦Intermediary agencies fail to exercise strict oversight during corporate standardization evaluations, and do not fully fulfill their responsibility to serve enterprises and ensure quality control. During the evaluation of Shunte’s work safety standardization in October 2012, it was found that there were significant shortcomings in the company’s daily construction management: no plans had been formulated, and hazard identification had not been carried out properly. As a result, all 10 points possible were deducted; this was the only item for which full points were lost. However, this issue was not listed separately when summarizing the main problems, thus failing to draw the company’s serious attention and prompt corrective actions. Additionally, it did not provide safety regulatory authorities with any targeted areas for supervision ； During the evaluation, illegal construction activities by the enterprise were detected; it was also known that the said facility was still in the approval phase and should not yet be constructed. Yet, on the grounds that it had not started operations, the full 100 points allocated for this criterion were not deducted as required, resulting in the enterprise’s overall score meeting the requirements for level 3 standardization. ⑧The safety supervision work by the Safety Supervision Bureau in Dongzhou District, Fushun City is inadequate. The Safety Supervision Bureau of Dongzhou District is responsible for the daily supervision and management of safety production at Shunte Company. During its routine inspections of this company, it failed to fulfill its duties properly and did not effectively prevent the company from engaging in illegal construction and production activities. II. Emergency rescue in case of accidents: Upon the occurrence of an accident, Shunte Company immediately takes measures for self-rescue, reports the incident to the relevant authorities, and also calls the 110 emergency center. Upon receiving the accident report, the top leaders of Fushun City, along with heads of relevant departments such as those in charge of work safety, environmental protection, and public security, rushed to the accident site immediately to organize rescue efforts. Fushun City activated its emergency response plan for hazardous chemical accidents, established a rescue command center, and mobilized police, firefighters, and medical personnel to carry out emergency rescue efforts. The Fushun Petrochemical Branch and the Fushun fire department dispatched a total of 122 firefighters, along with 19 fire trucks, to fight the fire. At the same time, they contained and collected firefighting water, which was then discharged into the wastewater treatment plant of the adjacent Fushun Petrochemical Acrylic Fiber Plant. Rescue personnel provided cooling protection for the pipes, trays, and framework in the accident site’s tank area, and carried out firefighting operations in that area. At 18:00, the fire was extinguished. At 24:00, the remaining contents in the tank were pumped out and sent to the acrylic fiber plant of the petrochemical company for harmless treatment. III. Reflections and Recommendations (1) It is necessary to firmly establish and implement the scientific outlook on development. All counties and districts**, along with their relevant departments and various production and business entities, must draw serious lessons from the tragic explosion and fire accident at the Shunte Company on September 14th, apply these lessons to similar situations, and make significant efforts to strengthen safety measures in production, particularly in the field of chemical manufacturing. Starting from the basics, more resolute, forceful, and effective measures should be taken. By improving systems, establishing sound regulations, and innovating mechanisms, as well as by strengthening responsibilities, management, and supervision, and by ensuring strict law enforcement, rigorous evaluation, and serious accountability, it is necessary to truly implement the safety production responsibility system along with the related tasks and measures, thereby firmly consolidating the foundation for enterprise safety production and **safety supervision. (II) Thoroughly learn from the lessons of the accident and carry out in-depth work to crack down on illegal and irregular activities. All counties and districts **must continue to carry out the efforts to crack down on illegal and irregular activities in the field of work safety, in accordance with the requirements set out in the \"Notice of the General Office of the State Council on Carrying Out Special Campaigns to Crack Down on Illegal and Irregular Activities in Work Safety\" (Guo Ban Fa [2012] No. 10), as well as the relevant directives from the State Council’s Work Safety Committee. The Dongzhou District **must, in light of the fact that there are numerous hazardous chemical-related construction projects in the Fushun High-Tech Industrial Development Zone under its jurisdiction, further improve relevant mechanisms, clarify responsibilities, and assign tasks. It should continue to strengthen leadership over efforts to crack down on illegal and irregular activities, maintain a strict stance against such behaviors, and severely punish illegal subcontracting, contracting, as well as any illegal or irregular production, construction, and business operations. In particular, those who violate the law will be held strictly accountable in accordance with the law. Efforts should be made to establish a long-term mechanism for cracking down on illegal and irregular activities. Publicly disseminate the lessons learned from this incident; identify typical cases and impose severe punishments. Through concrete actions, we must rectify the erroneous notion of “getting on board first and paying later”, thereby eliminating inherent risks stemming from illegal and unlawful construction activities. (III) Effectively implement the primary responsibility of enterprises for work safety, and put accident prevention measures into practice. Sunte Company and other chemical enterprises must earnestly draw lessons from this tragic explosion and fire accident, fully assume their responsibility for ensuring safe production, and treat safety measures as a top priority for the company. First, it is necessary to establish and improve, in accordance with the law, safety production responsibility systems for managers and employees at all levels, and to ensure their implementation and assessment at each level. Secondly, it is necessary to improve job operation procedures in accordance with relevant laws and regulations and enforce them strictly to ensure their proper implementation. Third, it is necessary to further strengthen the safety management of operations such as hot work, entry into confined spaces, and the installation or removal of blind flanges. It is essential to follow relevant regulations strictly, enhance risk identification, ensure thorough verification of conditions, issue proper work permits, and maintain strict on-site monitoring in order to guarantee the safety of such operations. Fourth, it is necessary to strengthen safety education and training for employees, so as to foster a safety awareness among them. In particular, for newly hired employees and those changing positions, it is essential to ensure the quality of education and training. Rigorous assessments must be conducted; those who fail the assessments or do not meet the job requirements are strictly prohibited from taking up their posts. Fifth, we must thoroughly promote the development and implementation of work safety standardization. We should adhere to high standards and strict requirements. Starting from the planning, organization, schemes, measures, and contingency plans for each post and every operational activity, we need to identify any deficiencies or imperfections in relevant systems and regulations. We must also delve into the underlying reasons why these systems and regulations are not being properly implemented. Additionally, we should increase investments in safety efforts. A comprehensive and meticulous assessment must be conducted regarding the controllability of risks in the enterprise’s processes, the integrity of equipment and facilities, the effectiveness of safety management, as well as the competence and adaptability of all personnel. Any problems identified during this self-inspection must be fully rectified. (IV) Strictly assess the safety conditions that Shunte Company must meet to resume production activities. Shunt Company needs to commission an evaluation agency with Class A qualifications for chemical production to conduct another comprehensive safety assessment of the company. Once the evaluation agency confirms that the existing problems have been rectified, the company must submit an application to the municipal work safety supervision bureau with the approval of the district work safety supervision bureau. The municipal work safety supervision bureau will then organize experts to conduct a review, and production activities can only commence once the review is approved. Production activities are strictly prohibited without passing the review. (5) Guided by the \"Guiding Opinions on Strengthening the Safety Management of Inspection, Maintenance, and Repair Operations in Chemical Enterprises across the Province\" issued by the Provincial Bureau (Liaonan Supervision No. 3206), efforts should be made to further enhance the management of such operations in chemical enterprises. Relevant enterprises must implement the requirements set out in the Provincial Bureau’s \"Guiding Opinions on Strengthening the Safety Management of Inspection, Maintenance, and Repair Operations in Chemical Enterprises across the Province\" in order to minimize safety risks. First, it is necessary to establish and improve safety management systems and operating procedures for inspection, maintenance, and repair work, clarify the work processes and approval systems, and enforce them strictly. Second, it is necessary to strengthen the organizational leadership over inspection and maintenance work: establish a dedicated organization, clarify responsibilities and tasks, have leaders take charge personally, and exercise focused control over key aspects. Thirdly, it is necessary to formulate comprehensive, scientific, safe, and reliable maintenance plans. Proper organization, coordination, and safety supervision of maintenance operations must be ensured, with responsibilities clearly assigned to individuals. Additionally, emergency response plans for the maintenance process should be developed and implemented. For major maintenance tasks, a sound maintenance plan should be formulated based on consultations with experts and relevant institutions. Fifth, it is necessary to strictly enforce the management system for changes in processes, equipment, and facilities. All changes must be implemented only after thorough scientific evaluation, and subsequent education, training, and assessment must also be carried out. (VI) It is necessary to strengthen the safety supervision responsibilities of local authorities at all levels and their relevant departments, and to enhance the supervision of safety in hazardous chemical enterprises. Local governments at all levels **and their relevant departments should step up law enforcement and supervision efforts. Guided by the spirit of Vice Governor Pan’s speech at the on-site meeting on the safe production of hazardous chemicals held in the province on July 23, we should focus on the key tasks at the provincial, municipal, and local levels, refine work plans, intensify efforts in governance and rectification, and ensure that safety supervision responsibilities are implemented in a more detailed and thorough manner ； Strictly supervise the evaluation of safety production standardization in accordance with laws and regulations; conduct spot checks on enterprises that have met the standards using stricter criteria, so as to urge these enterprises to effectively assume their primary responsibilities and improve their safety management levels ； By urging hazardous chemicals enterprises to strengthen their awareness of safe production, obtain regulatory information in a timely manner, enhance their risk control capabilities, and improve the safety level of plant operations ； Urge enterprises to handle process changes in a serious and scientific manner ； Strengthen the safety management of chemical processes, including emergency response, contractor management, and operation safety management ； Focusing firmly on the \"two key points and one major aspect\" as the core of safety supervision, efforts are made to drive enterprises to improve their inherent safety levels in terms of equipment, facilities, and management.