The investigation into the accident in which three people died from hydrogen sulfide gas poisoning at Gansu Yaobang Company has concluded.

“The Gaotai County Party Committee and County Government failed to rigorously implement the state, provincial, and municipal policies, laws, and regulations on work safety and environmental protection; the Gaotai Branch of the Zhangye Municipal Ecology and Environment Bureau exhibited serious negligence in oversight and management of the project; Yaobang Company’s safety management was chaotic… The Gaotai County Party Committee and County Government are hereby instructed to submit a written self‑criticism; the Gaotai Branch of the Zhangye Municipal Ecology and Environment Bureau and other relevant responsible entities are likewise directed to submit written self‑criticisms; Yaobang Company is ordered to immediately cease all construction and trial‑production activities, and shall not resume production without passing acceptance inspection or if such inspection is deemed unsatisfactory.”

On September 14, a major hydrogen sulfide gas poisoning incident occurred at the wastewater treatment plant of Zhangye Yaobang Chemical Technology Co., Ltd. in Gansu Province (hereinafter referred to as Yaobang Company), resulting in three fatalities and direct economic losses amounting to RMB 4.5 million. Recently, the Emergency Management Bureau of Zhangye City released the accident investigation report.

An on-duty operator at the enterprise’s wastewater treatment plant caused an accident by violating operating procedures.

Yaobang Company is an enterprise engaged in the manufacture of biochemical and microbial pesticides. In November 2019, the company completed construction of its own wastewater treatment plant, which comprises effluent ponds No. 1 through No. 7, a neutralization workshop, a triple-effect evaporation workshop, and associated biochemical treatment facilities.

According to the environmental impact assessment report, upon completion of the existing 1,500‑ton‑per‑year production project for “2‑methylamino‑5‑tert‑butyl‑1,3,4‑thiadiazole,” the original wastewater treatment facilities will be utilized. The process—comprising neutralization, vacuum distillation, and triple‑effect evaporation—will be employed, after which the exhaust gases will be routed to Workshop No. 1, where they will be treated by the exhaust gas treatment system associated with the triphenylchloromethane unit.

On-site inspection revealed that the tail‑gas treatment system intended to support the triphenylchloromethane unit had not been commissioned. The enterprise installed an additional induced draft fan in the existing wastewater neutralization workshop and carried out modifications to Wastewater Pools 1 through 7, the neutralization kettle in the neutralization workshop, and the tail‑gas absorption pipeline in the triple‑effect evaporation workshop. Furthermore, a new alkaline scrubber was added on the east side of the neutralization workshop, with the tail gas routed to this scrubber for treatment. Following the implementation of the “neutralization + vacuum distillation + triple‑effect evaporation” process, the tail gas is now directed to the alkaline scrubber on the east side of the neutralization workshop for treatment.

On September 14, 2020, on-duty personnel at the enterprise’s wastewater treatment plant violated operating procedures by rapidly adding hydrochloric acid to Wastewater Pool No. 6, which contained a large amount of sulfides, in an attempt to neutralize them. This resulted in the rapid release of substantial quantities of hydrogen sulfide gas within a short period. Furthermore, the on-duty personnel entered the hazardous area without wearing appropriate personal protective equipment and inhaled high concentrations of hydrogen sulfide and other toxic gases, leading to poisoning and the deaths of three individuals.

Enterprise management is chaotic, and the “three simultaneous” system—requiring the concurrent implementation of safety facilities, pollution prevention measures, and occupational disease protection facilities—has not been strictly enforced.

The investigation report concluded that the “September 14” accident was a major production safety liability incident in which responsible officials of the enterprise violated relevant environmental protection laws and regulations by unilaterally altering the wastewater treatment process without undergoing design, assessment, or approval, while on-duty personnel at the wastewater treatment plant failed to comply with operating procedures, resulting in poisoning and fatalities.

The company involved, Yaobang Co., Ltd., suffered from chaotic safety management, failed to rigorously implement the “three simultaneous” system for safety facilities, pollution prevention measures, and occupational disease protection facilities, unilaterally altered its wastewater treatment process, conducted emergency response in a perfunctory manner, and installed and operated safety equipment in non-compliance with applicable laws and regulations.

The Gaotai County Party Committee and the Gaotai County People’s Government failed to rigorously implement the state, provincial, and municipal policies, guidelines, laws, and regulations on work safety and environmental protection; they also failed to detect and address the failure of entities such as the Gaotai Branch of the Zhangye Municipal Ecological Environment Bureau to faithfully perform their regulatory duties.

The Gaotai Branch of the Zhangye Municipal Ecology and Environment Bureau failed to supervise enterprises in strictly implementing the “three simultaneous” system for pollution prevention and control measures; it did not identify or rectify issues such as Yaobang Company commencing construction of its wastewater treatment system without completing the required environmental impact assessment procedures, nor putting the facility into operation before fulfilling the prescribed environmental protection completion‑acceptance requirements. Furthermore, the branch did not rigorously perform its duties of comprehensive administrative law enforcement inspections for ecological and environmental protection, overlooking the wastewater discharge practices of Yaobang Company’s wastewater treatment plant and failing to conduct the mandated inspections and monitoring of the operation and compliance of the company’s production‑wastewater treatment facilities and equipment, as well as its effluent discharge. Even after becoming aware that the enterprise had put its wastewater treatment facilities into service without completing the required acceptance inspection, the branch failed to promptly halt and correct this illegal act in accordance with relevant laws and regulations, allowing the situation to persist until an accident occurred. Additionally, the branch did not adequately carry out inspections of the enterprise’s environmental protection facilities nor issue timely administrative enforcement decisions, resulting in serious mismanagement and oversight of the project’s construction.

The Gaotai County Party Committee and County Government, the Gaotai Branch of the Zhangye Municipal Ecology and Environment Bureau, and other relevant responsible entities are hereby required to submit written self-criticism reports.

Based on the analysis of the accident’s causes and its nature, the investigation report puts forward recommendations for disciplinary action against the personnel and entities found to be responsible.

Of the 27 persons held accountable, one was exempted from liability due to death in the accident; three were referred to the judicial authorities; two received administrative penalties; and three were ordered by the enterprise involved to be dismissed. Additionally, two were given a major demerit, five a demerit, three a warning, six underwent admonitory talks, and two submitted written self-criticism reports.

Yao Bang Company is ordered to immediately cease all construction and trial‑production activities and to promptly complete the requisite procedures in strict compliance with national regulations requiring that safety facilities, pollution‑prevention measures, and occupational disease‑prevention facilities for construction projects be implemented concurrently. Production may not be resumed without prior acceptance inspection, or if such inspection reveals non‑compliance.

It is recommended that the Zhangye Municipal Emergency Management Bureau impose a fine of RMB 990,000 on Yaobang Company and include the company and its relevant personnel in the list of entities subject to joint punitive measures for breaches of work safety regulations. Furthermore, it is recommended that the Gaotai Branch of the Zhangye Municipal Ecology and Environment Bureau and the Gaotai County Health Commission, in accordance with applicable laws and regulations, impose administrative penalties for the company’s unlawful conduct.

The Gaotai Industrial Park Management Committee, the Gaotai Branch of the Zhangye Municipal Ecology and Environment Bureau, the Gaotai County Emergency Management Bureau, the Gaotai County Health Commission, and the Luocheng Town Government are hereby instructed to submit written self-criticism reports to the Gaotai County Party Committee and the Gaotai County People’s Government.

The Gaotai County Party Committee and County Government, together with the Zhangye Municipal Emergency Management Bureau, have been instructed to submit a written self-criticism to the Zhangye Municipal Party Committee and Municipal Government.

It is understood that, in the next phase, Zhangye City will draw profound lessons from the accident, apply these lessons more broadly, conduct thorough inspections and remediation of safety hazards, effectively eliminate potential risks, and rigorously prevent and curb all types of production safety incidents.

Source: China.org.cn