Qilu Petrochemical was fined 900,000 yuan for the \"May 18\" poisoning incident

Accident Investigation Report: Recently, the Zibo Emergency Management Bureau released the investigation report on the \"5·18\" poisoning accident at the Qilu Branch of Sinopec Corporation. The direct cause of the accident was that the operators of Hansheng Company’s testing equipment entered a confined space without wearing protective gear, inhaling hydrogen sulfide gas emitted from the sludge in the testing equipment’s reaction chamber, which led to acute poisoning and death.

The main contents of the accident investigation report are as follows: I. Basic Information (1) Water Supply and Treatment Plant The water supply and treatment plant is located at No. 2, Yixing North Road, Linzi District. Its primary function is to supply fresh water, recycled water, and chemical-treated water to the various production facilities of Sinopec Qilu Branch; it also handles wastewater from these facilities as well as from some local enterprises. The water supply and drainage plant consists of 8 workshops and 4 management departments, with a total of over 780 employees. Refining water treatment workshop. The Refining Water Treatment Workshop is one of the 8 workshops under the Water Supply and Drainage Plant. Based on their location, the workshop is divided into four units: the Water Services South Unit, the Water Services North Unit, the Purification South Unit, and the Purification North Unit. The workshop employs a total of 156 people. This accident occurred in the Purification South Area unit. The Purification South Area is located at No. 3809, Xinhua Road, Linzi District, and is in the same compound as the First Sulfur Workshop of the refinery belonging to Qilu Branch of Sinopec Corporation (hereinafter referred to as the refinery).

(III) Information on sludge in the refinery water treatment workshop 1. Generation and treatment of sludge The wastewater treatment process in the refinery water treatment workshop consists of oil separation → flotation → biological treatment. Sludge is an oily solid-liquid mixture that arises from the flotation process. According to the **List of Hazardous Wastes (2021 edition)**, sludge is classified as a hazardous waste, with the code: 251-004-08. The wastewater treatment plants in the South Purification Area and the North Purification Area both generate scum, which can be disposed of by hazardous waste management companies or sent to the coking units of refineries for incorporation into the process. Based on the operating conditions of the coking unit, the refinery plans to stop receiving sludge from the refinery wastewater treatment plant in the future. Therefore, to reduce the costs associated with outsourcing the disposal of hazardous waste, it is necessary to minimize the amount of sludge. 2. Sludge reduction treatment: In 2022, the water supply and drainage plant entered into contracts with Anxingda Company and Kaimike Company. These two companies were tasked with installing portable sludge reduction treatment units at the refinery’s water treatment facilities, in order to handle the sludge from the North purification area and the South purification area. The sludge cakes generated as a result of the filtration process in these treatment units also constitute hazardous waste (code: 251-002-08), and it is necessary to entrust specialized hazardous waste disposal companies to handle them. The cooperation process between the water supply and drainage plant and the 2 companies is as follows: technical exchange → installation of test devices on-site → trial operation of the devices → approval of the test results → participation in bidding to select a supplier → signing of a contract after winning the bid → official operation of the devices. When an accident occurred at Hansheng Company’s skid-mounted testing facility, it had not yet officially entered the testing phase. 3. Hydrogen sulfide in the scum: The purification area in the refinery water treatment plant has a 1000 m3 scum tank, with the tag number G3103; at the time of the incident, it was connected to Hansheng Company’s scum reduction test apparatus via pipelines. After the accident, the accident investigation team entrusted the Inspection and Metrology Center of Qilu Branch of Sinopec Corporation to analyze the water and gas samples taken from tank G3103. The sulfide content in the water samples was 51.6 mg/L, while the hydrogen sulfide content in the gas at the middle part of the tank was 130 mg/m3. The main danger of scum is the hydrogen sulfide gas dissolved in it, which can easily evaporate when disturbed. The \"Detailed Rules for the Safe Management of Hydrogen Sulfide Protection at Qilu Petrochemical Co., Ltd.\" issued by its Qilu branch in 2018 stipulate that: \"In operations where the hydrogen sulfide concentration may exceed 30 mg/m3 (20 ppm), positive-pressure air respirators must be worn.\"

Main physical and chemical properties and hazard information of hydrogen sulfide Boiling point: -60.3℃； Relative vapor density (air=1): 1.19 ； Lower explosion limit: 4.3% ； Soluble in water, ethanol, gasoline, etc. Hydrogen sulfide is a potent neurotoxin; its LC50 is 618 mg/m3 (444 ppm) for inhalation by rats, while the LCLo is 600 ppm for 30 minutes of inhalation by humans. The Occupational Exposure Limit (MAC) in workplaces is 10 mg/m3.

(IV) Progress of Hansheng Company’s sludge reduction project 1. Technical exchanges Although Hansheng Company hopes to win the bid for the sludge reduction treatment project at the water supply and drainage plant, it does not possess the relevant technologies for such treatment. Therefore, Qiu Kangkang reached out to Qi Bing and Liu Zhidan, with whom he had previous business relationships, to collaborate. Qi Bing is the legal representative of Liaoning Renren Sewage and Sludge Treatment Co., Ltd., as well as the technical manager of Panjin Furuida Environmental Protection Technology Co., Ltd. (hereinafter referred to as Furuida Company). The three of them agreed to work together to undertake the sludge reduction project for the water supply and drainage plant under the name of Hansheng Company: Qi Bing was responsible for providing the main equipment, technology, and personnel needed for the project, Liu Zhidan was in charge of handling the wastewater-related aspects of the project, and Qiu Kangkang was responsible for coordinating with the water supply and drainage plant. Hansheng Company first collected scum samples from the refinery water treatment workshop and sent them to Liaoning, where Qi Bing conducted pilot tests on them. After receiving the pilot test results provided by Hansheng Company, the water supply and drainage plant was satisfied with the test data and decided to engage in technical exchanges with them. On December 16, 2021, Qiu Kangkang, Xue Lei, Qi Bing, and Liu Zhidan met with the technical staff from the water supply and drainage plant on behalf of Hansheng Company. Following the meeting, the water supply and drainage plant agreed to allow Hansheng Company to install testing equipment on-site. The Production Technology Department took the lead in coordinating with Hansheng Company to prepare the \"Technical Plan for Reducing Sludge in the Southern Refining Water Treatment Area of the Water Supply and Drainage Plant of Sinopec Qilu Branch\" (hereinafter referred to as the \"Technical Plan\"). In the refinery water treatment workshop, Zhu Lijun, the technical team leader, is in charge of this sludge reduction experiment project and is responsible for coordinating with Hansheng Company regarding related tasks. While preparing the \"Technical Plan,\" Hansheng Company began to arrange for the main testing equipment to be transported to the refinery water treatment workshop site for installation. 2. On-site installation of the test apparatus: Hesheng Company assigned Yuan Wei from Zibo Beiyue Equipment Protection Engineering Co., Ltd. to be responsible for the assembly and installation of the scum reduction test apparatus. The Refining Water Treatment Workshop designated the location for on-site equipment installation for Hansheng Company: in the southwest corner of Plot No. 3809 on Xinhua Road, on the open space to the south of the storage area in the Purification South Zone, and relatively close to the scum tank G3103. In February 2022, the equipment from Hansheng Company began to arrive at the site; installation started in March and was completed in early April. During the equipment installation in March, in accordance with the wiring locations specified by Zhu Lijun, Hansheng Company connected the water, steam, and scum pipeline systems of its testing apparatus to the corresponding pipelines and equipment in the refinery water treatment workshop; the scum pipeline was connected to the original hose of the G3103 scum tank. The power supply required for the testing equipment is sourced from the power distribution room in the Refining Electrical Workshop of the Operation and Maintenance Center of Qilu Branch of Sinopec Corporation (the “Yi Wu Substation”). Cables are laid from this distribution room to the on-site power distribution cabinet of Hansheng Company’s testing equipment; power was supplied to this cabinet on April 25th. At the dross reduction test facility of Hansheng Company, in addition to Qiu Kangkang and Liu Zhidan, the on-site workers also included Lu Song, Wang Zhen, and Jiang Wei. Among them, Lu Song and Wang Zhen are employees of Furuida Company, assigned by Qi Bing to work on the scum reduction project at Hansheng Company ； Jiang Wei is Liu Zhidan’s cousin’s son and worked at Furuida Company in 2021.

3. On-site layout of the testing apparatus: The basic principle of Hesheng Company’s sludge reduction testing apparatus is to separate water, oil, and sludge through methods such as heating, chemical addition, and centrifugation, thereby achieving the goal of reducing sludge volume. The on-site installation consists mainly of 3 skid-mounted containers, each of which is commonly referred to as a “skid.” All three skids are 2.5 meters in height; the heating and reaction skid located on the west side is 5.98 meters long and 2.25 meters wide, while the other two skids are 6.1 meters long and 2.24 meters wide. As shown in the figure above, the heating reaction \"pivots\" to divide the interior into 3 separate chambers: the reaction chambers are located at both ends, while the buffer chamber is in the middle. Feeding is carried out by using a feed pump to push the scum from G3103 into the reaction chamber of the testing device. In the northwest corner at the top of each of the 3 chambers, there is a manhole measuring 50cm×50cm; the manhole in the northern reaction chamber was the location where the accident occurred. At the test facility, there are also equipment and facilities such as centrifuges, filter presses, chemical storage tanks, pumps, and power distribution cabinets.

II. Course of the accident and rescue and follow-up actions (I) Course of the accident On May 16, 2022, Qiu Kangkang informed Liu Zhidan and Lu Song by phone that the Refining and Water Treatment Workshop had given permission for Hansheng Company’s testing equipment to begin operations. At around 8:20 on May 17, Qiu Kangkang, Liu Zhidan, Lu Song, Wang Zhen, Jiang Wei, and four others arrived at the site of the testing apparatus. Qiu Kangkang informed Zhu Lijun by phone that the test setup on site needed to be tested with fresh water, and Zhu Lijun agreed. In the morning, the on-site staff of Hansheng Company conducted trial operations on each pump. At around 16:00 on May 17, the staff from Hansheng Company entered the site again, and Lu Song, Wang Zhen, and Jiang Wei continued with the machine testing. At around 17:00, the testing apparatus fed material from the G3103 scum tank; Lu Song entered the northern reaction chamber of the heating reaction unit via the ladder inside the manhole, and collected scum samples using plastic buckets. After that, Lu Song and Liu Zhidan returned to their accommodation and used the scum samples for pilot tests. That night, no test results were obtained until the scum samples were used up. On the morning of May 18, Lu Song sent Wang Zhen and Jiang Wei to the test facility to take samples again. At 6:40 on May 18, Wang Zhen and Jiang Wei entered the site of the testing apparatus. At 7:20 and 7:50, Lu Song tried to contact Wang Zhen and Jiang Wei by phone on two occasions, but was unable to get through. At around 8:10, Lu Song arrived at the site of the testing apparatus. Through the manhole opened in the north reaction chamber, he saw that the level of the scum in the chamber was about 80 cm, with Wang Zhen and Jiang Wei lying motionless inside the scum.

II) Emergency response to the accident and follow-up actions: Upon seeing the situation in the north reaction chamber, Lu Song quickly shouted for help. Lu Yuguang, an employee of Tiancheng Construction Company who was working about 30 meters to the east of Hansheng Company’s testing facility, heard the cries for help and immediately rushed to the scene to assess the situation. He stopped Lu Song, who was panicked and trying to enter the reaction chamber to rescue people, and called Zhu Li** to inform him of what had happened. Upon receiving the call, Zhu Lijun rushed to the scene immediately, and along the way called the control room in Purification South Area to have people bring air respirators to the accident site to assist with the rescue efforts. Upon arriving at the scene, Zhu Lijun, along with operators Wang Yuedong and Zhang Xin, tried to pull the person out using a wooden pole tied with a hook, but they were not successful. During that time, Qiu Kangkang received a call from Zhu Lijun, and Liu Zhidan received a call from Lu Song; the two of them immediately rushed to the scene. At 8:40, Zhu Lijun called Wang Honghai, the director of the Refining and Water Treatment Workshop, to report the accident, and the accident details were then reported up the chain of command. At 8:51, Xu Chunpeng, the safety engineer at the refining and water treatment workshop, called the 120 emergency service ； At 8:55, Zhu Lijun called the emergency rescue number of Qilu Petrochemical Fire Brigade. Before the fire and rescue workers arrived, at Zhang Xin’s suggestion, Liu Zhidan and Lu Song removed a pipe cap from the bottom of the north reaction tank in order to discharge the scum inside it. At 9:02, fire and rescue personnel arrived at the scene to carry out rescue operations. At 9:07, emergency medical services arrived at the scene. At 9:06, Feng Baoshan, the safety director of the water supply and drainage plant, called the emergency management bureau’s duty phone to report the accident. Upon receiving the report, the top officials of the city’s Emergency Management Bureau rushed to the water supply and drainage plant at once to oversee the on-site rescue efforts and emergency response. Around 10 o’clock, Wang Zhen and Jiang Wei were rescued one after another, and emergency medical personnel on the scene confirmed that both of them had died. After the accident, the relevant parties discussed matters related to aftermath handling with the family of the deceased. The deceased’s body was cremated at the Qingzhou City Funeral Home on June 8, and the follow-up work related to the accident has been largely completed.

III. Causes and nature of the accident (1) Direct cause: The operators of Hensheng Company’s testing equipment entered a confined space without wearing protective gear, inhaling hydrogen sulfide gas emitted from the sludge in the testing equipment’s reaction chamber, which led to acute poisoning and death. (II) Indirect causes: 1. Inadequate safety management at Hansheng Company. Proper safety operating procedures for the scum reduction testing equipment have not been established; necessary protective gear has not been provided to the workers; and no safety training has been given to them. 2. The water supply and drainage plant fails to provide unified coordination and management for the safe production of its collaborating units. There was inadequate on-site safety inspection and monitoring of Hansheng Company’s scum testing equipment, failing to detect and prevent workers from entering restricted areas for work in violation of regulations. (III) Nature of the accident: Upon investigation, this accident was determined to be a routine work safety liability accident.

IV. Determination of Accident Liability and Recommendations for Handling (I) Persons whose criminal liability is recommended to be pursued: 1. Qiu Kangkang, the key person in charge of Hansheng Company and the organizer of the sludge reduction testing experiment, bears primary responsibility for the occurrence of the accident. It is suspected of constituting a criminal offense; it is recommended to hand it over to the judicial authorities for investigation and handling in accordance with the law. 2. Qi Bing, who organized the participants of the scum reduction test device, is held fully responsible for the occurrence of the accident. It is suspected of constituting a criminal offense; it is recommended to hand it over to the judicial authorities for investigation and handling in accordance with the law. (II) Entities and individuals recommended for administrative penalties It is recommended that the Municipal Emergency Management Bureau impose administrative penalties on the following entities and individuals in accordance with the relevant provisions of the Work Safety Law of the People’s Republic of China: 1. Hansheng Company, which bears primary responsibility for the occurrence of the accident, shall be punished in accordance with Article 114 of the Work Safety Law of the People’s Republic of China. 2. Qilu Branch of Sinopec Corporation bears significant responsibility for the occurrence of the accident, and shall be punished in accordance with Article 114 of the Work Safety Law of the People’s Republic of China. 3. Li Yudao, the person in charge of the water supply and drainage plant, failed to ensure proper supervision and inspection of safety measures within his unit; he is therefore held accountable for the occurrence of the accident. He is punished in accordance with Article 95 of the Work Safety Law of the People’s Republic of China. V. Accident Prevention and Rectification Measures To draw lessons from the accident, implement the principle of \"not letting go of any aspect related to the accident,\" and ensure proper safety management in the future to prevent similar incidents, the following rectification measures and suggestions are put forward: (1) Authorities at all levels, relevant departments, and various enterprises must thoroughly learn from the lessons of this accident, strengthen their awareness of critical limits and bottom-line thinking, and strictly adhere to the requirements of \"shared responsibilities by the Party and government, dual responsibilities for each position, and joint management.\" They must also fulfill their duties diligently, carry out thorough risk assessment and control as well as identification and remediation of potential hazards, in order to fully address all safety risks. (II) Enterprises in various industries must strictly comply with the requirements of laws, regulations, standards and norms, and earnestly establish a dual prevention mechanism for safety risk classification control and hazard identification and rectification, so as to effectively strengthen safety production management. It is necessary to strictly standardize the procedures for hazardous operations such as working in confined spaces, hot work, work at heights, and temporary electricity use, and to strengthen safety management by addressing aspects such as risk identification, warning signs, analysis and testing, protective equipment, and on-site supervision. At the same time, ensure unified coordination and management of the safe production of the devices and equipment owned by contractors and outsourced construction teams within the production and operation sites, in order to completely eliminate any gaps in safety production management. (III) Relevant regulatory authorities shall earnestly fulfill their responsibilities for safety production supervision, continuously improve the level of such supervision, and urge various enterprises to strictly implement all safety production management systems. On the basis of strengthening daily safety production management, particular attention should be paid to managing contractors and overseeing hazardous operations. It is necessary to urge enterprises to assume their primary responsibilities, improve the safety assessments and safety diagnostics for the installation of experimental production facilities and temporary production units on site, in order to prevent all types of accidents.