Causes of two flash fire and flash explosion accidents during maintenance at Yangzi Petrochemical announced

Recently, Sinopec Yangzi Petrochemical Company Limited experienced two consecutive production safety accidents during the centralized major maintenance phase of its units. The two accidents occurred only 27 days apart, resulting in a total of 6 contractor worker deaths and 3 injuries.

The investigation preliminarily revealed that the two accidents exposed systemic loopholes in the company's safety management regarding maintenance and repair. Several management personnel have been dismissed, and relevant responsible persons have been subjected to criminal compulsory measures according to law.

“5・29” Olefin Division 1# Ethylene Unit Flash Fire Accident: 4 Contractor Personnel Killed

At 13:58 on May 29, 2026, a flash fire accident occurred at the major maintenance construction site of the 1# Ethylene Unit in the Olefin Division of Yangzi Petrochemical, causing the deaths of 4 contractor workers.

It is understood that Yangzi Petrochemical's 1# Ethylene Unit started a shutdown for major maintenance on May 14, simultaneously carrying out unit material withdrawal and material purging work. On May 24, the process disposal of the entire unit was completed, and after confirmation by the workshop, it was handed over to the maintenance unit to carry out construction work.

On May 29, the maintenance unit organized personnel to carry out the disassembly work of the cracking gas valve of cracking furnace BA-105. Around 13:50, the workers disassembled the valve outlet flange and used an angle grinder to cut the inlet flange bolts. At 13:58, combustible material leaked from the valve outlet flange, and the leaked material encountered sparks generated by the grinding, triggering a flash fire. The open flame at the scene lasted for about 6 minutes before being extinguished.

The direct cause of the accident was that the emptying and purging of the cracking gas pipeline were not thorough, leaving residual combustible materials inside the pipeline; after the cracking gas valve flange was disassembled, the material leaked out and encountered cutting sparks, causing a flash fire.

The investigation pointed out that the accident exposed multiple prominent safety hazards: there were major loopholes in the special operation approval and confirmation process, with prominent phenomena of proxy card swiping and proxy signing; maintenance risk identification and safety disclosure were mere formalities; high-risk operations at the site were superimposed, with pipeline disassembly and hot work being carried out simultaneously, and only the gas on the operation platform was detected without conducting combustible gas detection inside the pipeline; violations such as contractor personnel not matching their permits were not stopped in time; the professional competence of on-site custodial personnel was insufficient, making them unable to effectively perform their custodial duties; control over contractor access was not strict, and most workers lacked chemical maintenance experience; the unit equipment was seriously aged, safety hardware facilities had defects, and the personnel positioning system was not put into use as required.

“6・24” Aromatics Division Flash Explosion Accident: 2 Deaths and 3 Injuries

Less than a month after the “5・29” accident, at around 14:35 on June 24, 2026, a flash explosion occurred during the maintenance and reinstallation of tower trays in the sulfolane solvent recovery tower of the No. 2 Reformer Unit in the Reformer Work Area of the Aromatics Division of Yangzi Petrochemical, causing the deaths of 2 construction workers from Qilu Maintenance Company and injuries to 3 others.

Data shows that the No. 2 Reformer Unit shut down on May 7, and process purging was completed on May 16 along with the confirmation of safety handover conditions. The involved sulfolane solvent recovery tower is 44 meters high and has a total of 34 trays. On the day of the accident, the tray reinstallation work was carried out from bottom to top. At 13:30 on the afternoon of June 24, the work continued. At the time of the accident, two high-risk operations were being carried out simultaneously at the site: one was the reinstallation of trays inside the recovery tower, where 5 workers were using non-explosion-proof electric wrenches to tighten bolts inside the tower, and 1 person was monitoring outside the tower; the other was the replacement of the elbow on the gas-phase pipeline at the top of the tower, where workers were using an angle grinder to cut the corroded and thinned pipeline on the pipe section platform. The two operations were close to each other and the process pipelines were connected upstream and downstream, ultimately triggering a flash explosion.

Common Problems of the Two Accidents and Responsibility Disposition Results

The investigation determined that the causes of the two accidents were highly similar, collectively exposing a complete loss of control over safety management during this major maintenance of Yangzi Petrochemical's units, and that the control of special operations was in name only. Main problems include: chaotic management of equipment process handover, with some equipment lacking purging detection records and handover confirmation procedures, and starting work without completing joint inspections; lack of control over cross-operations, with simultaneous high-risk operations of multiple types and at multiple points without unified coordination and command; chaos in work permit management, with violations such as proxy signing and advance acceptance; on-site custodians failing to perform their duties and lacking risk identification ability; weak management of contractor access and safety training, and a lack of safety skills among frontline workers.

After the accidents, the pursuit of responsibility for relevant parties proceeded simultaneously. The Deputy General Manager of Yangzi Petrochemical, the Manager of the Olefin Division, and the Manager of the Aromatics Division have been dismissed from their posts; 4 relevant responsible persons have been criminally detained by public security organs according to law on suspicion of the crime of a major liability accident.

The two consecutive maintenance casualty accidents have sounded an alarm for the safety of major overhauls of units in chemical enterprises. The shutdown and maintenance of petrochemical units is a high-risk stage. Enterprises must strictly implement various systems such as process purging, energy isolation, special operation management, and contractor control, consolidate the responsibilities of territorial management and on-site custody, and strictly prevent the recurrence of similar accidents.