An explosion occurred during the maintenance of the heat exchanger in the isomerization unit of the BP refinery in Texas, resulting in 15 deaths and 170 injuries, with huge economic losses. This accident became a typical case of energy isolation failure in the global industrial sector.
Accident process and direct cause
During the maintenance of the feed pipeline of the heat exchanger at the plant, the blind plate for effective isolation was not installed as required, and only the upstream valve was closed. Due to the internal leakage of the valve, the hydrocarbon materials continued to leak, and eventually an explosion occurred due to the presence of a fire source. The core issue of the accident was the incomplete energy isolation, as relying solely on valve isolation could not eliminate the risk of material leakage. The hidden danger of valve internal leakage was not identified, and the chemical energy (pressure) in the pipeline was not thoroughly isolated and released, leading to an unexpected release of energy and causing a disaster.
Deep cause of the accident
Inadequate implementation of energy isolation standards: The enterprise did not strictly follow the "double valve isolation + blind plate" process system isolation standard, lowering the energy isolation requirements for high-risk pipeline operations, and overly relying on a single valve isolation.
Insufficient risk identification ability: The potential risks such as valve internal leakage were not fully considered, the assessment of the isolation effect of energy sources was insufficient, and there were no effective verification methods.
Defects in the safety management system: The enterprise prioritized production over safety, had insufficient safety investment, and inadequate safety training for employees, resulting in employees not strictly following the norms for energy isolation.
Failure of supervision and review mechanisms: No special review mechanism for the implementation of energy isolation measures was established, making it impossible to promptly detect and correct violations in the isolation process.
Accident lessons and corrective measures
Upgrade energy isolation standards: For high-risk process pipeline operations, mandatory implementation of "double valve isolation + intermediate release + blind plate isolation" multiple isolation measures is required, and closing the valve alone as an energy isolation method is strictly prohibited; blind plates should be numbered and managed, and a blind plate ledger should be established to ensure the traceability of the installation and removal process of blind plates.
Improve the isolation effect verification process: Use pressure testing, gas detection, etc., to confirm the zero-energy state of the isolated pipeline to ensure no risk of material leakage.
Strengthen safety culture construction: Establish the concept of "safety first", increase safety investment, strengthen employee safety training, and enhance employees' awareness of the importance of energy isolation and their ability to follow the norms strictly.
Establish an independent supervision and review mechanism: Establish a dedicated safety supervision department to conduct full supervision of the formulation, implementation, and verification of energy isolation measures, conduct regular safety audits, and promptly identify and rectify safety hazards.