Human Errors Lec. 13 PDF

Human errors Lec.13 By: Dr.Marwa Elkamel Introduction One of the most common causes of accidents in chemical industry is human error. In order to minimize the accident frequency and associated damage, a better understanding of the role played by human factor in such accident i...

Human errors Lec.13 By: Dr.Marwa Elkamel Introduction One of the most common causes of accidents in chemical industry is human error. In order to minimize the accident frequency and associated damage, a better understanding of the role played by human factor in such accident is prerequisite. The Human Factors Analysis and Classification System- Petrochemical Enterprise Fire and Explosion (HFACS-PEFE) model is established to examine the mechanism of human failure Human errors?? Human error is one of the most critical contributory factors in various accidents in different industries, including aviation, healthcare, transportation, and manufacturing. Many studies have pointed out the fundamental role of human errors in accident occurrence, with them being involved in 70–80% of aviation accidents, 60% of petrochemical accidents, 90% of road traffic accidents, over 90% of nuclear accidents, over 75–96% of marine accidents, and over 80% of chemical process accidents. For this reason, deaths and injuries or health problems, financial losses, non-financial losses, and environmental damages happen due to human errors Human errors?? Although many regulations, standards, and policies apply in the chemical industries, accidents still happen. it is necessary to analyze the causes of chemical accidents to prevent incidents involving death or personal injury, provide safety, and reduce environmental and economic losses in the chemical industries chemical accidents in South Korea between 2008 and 2018, and human error was the reason for 76.1% of all chemical accidents. Human factors were the leading cause of process accidents’ unsafe behavior HFACS The Human Factors Analysis and Classification System (HFACS) is one method originally developed for the aviation industry, which became popular and is widely used in safety domains in all industries. Shappell & Wiegmann (2017) based this method on James Reasons Swiss Cheese Model of active and latent failures , then divided the failures into 4 (four) different levels: (1) Unsafe Acts; (2) Preconditions for Unsafe Acts; (3) Unsafe Supervision; and (4) Organizational Influence HFACS-PEFE According to the model, violations, intellectual limitations, inadequate supervision, and insufficient safety culture are the most essential elements in the occurrence of accidents. Both direct causes and latent human failures involved in chemical industry accidents are identified and are then analyzed. The HFACS model framework The HFACS Model The HFACS is a conceptually technique for analyzing how human factors contribute to accidents. The combined system investigating active and latent factors has increased the reliability of the HFACS in accident investigation. According to the HFACS model framework, many deficiencies that lead to accidents are identified within four levels of human failures: organizational influences, unsafe supervision, preconditions for unsafe acts, and unsafe acts. Active Error, Latent Error Active Error Latent Error An active error refers to a mistake Latent errors are system-level flaws or made by an individual that has hidden conditions that lie dormant immediate effects. These are often until triggered by a specific event or caused by front-line operators. action. Example: Example: A worker mistakenly opens a wrong The emergency shutoff valve in a valve during a chemical mixing chemical plant has been poorly process, leading to an uncontrolled maintained for years due to budget reaction and release of toxic fumes. constraints. During an actual emergency, the valve fails to operate, This error directly results in an exacerbating the incident. The error incident and poses an immediate was embedded in the system and only hazard. surfaced during the event.  Decision Errors Perceptual Errors Example: Selecting an incompatible Example: Misinterpreting a gauge chemical during a mixing process due reading during high-pressure system to a misunderstanding of the chemical monitoring. properties. Explanation: The operator misjudges the safety data sheets (SDS) or skips Explanation: Poor lighting, fatigue, or verification due to time pressure, improper calibration might cause the leading to dangerous reactions. operator to perceive the situation incorrectly, leading to unsafe decisions. Skill-Based Errors Example: Accidentally opening the wrong valve, causing a release of hazardous chemicals. Explanation: This can occur due to a lapse in concentration or a lack of familiarity with the equipment.  Violations Violations occur when workers knowingly deviate from established procedures. These are categorized as: Routine Violations: Exceptional Violations: These are habitual actions These occur in response to unusual performed by workers to save time situations where workers believe or effort, often tolerated by the the rules do not apply or are organization. unaware of the proper protocol. Operators routinely bypass safety Example: interlocks to speed up the process During an unexpected system of transferring chemicals, despite shutdown, a worker improvises a being trained on the proper temporary fix by manually procedure. connecting two incompatible hoses, leading to a chemical spill. Chemical Accidents Although many chemical accidents have been caused by a combination of human and technical errors, accidents due to human error are unavoidable and difficult to control. Chemical accidents due to chemical labeling problems, lack of understanding of chemicals, or both were also classified as human errors. Chemical accidents were caused by non-compliance of certain hazardous chemical regulations, and this was caused by ignorance or misunderstanding. Therefore, chemical, physical, and hazardous properties of the product should be well documented and made through proper labeling, documentation,and emergency response procedures Human error Human errors, such as violations, intellectual limitations, inadequate supervision, and poor safety cultures, were the most essential factors responsible for fire and explosion accidents. Human errors include lack of work permits, inadequate analysis of risks, and inadequate training in the use of safety procedures. Defects in process facilities, which have resulted in accidents and deaths in Chinese oil industries in the past decade, were due to human factors. HUMAN ERROR TYPES OF ERRORS Analysis of accidents occurring in chemical plants using RCA analysis. There were only two violations caused by workers’ non-compliance with laws and regulations at the chemical plant, confirming that the safety awareness of workers also improved as the safety law was strengthened. However, as a result of classifying accidents caused by human error, it was found that action errors caused more chemical accidents than thinking errors. It is well known that slips and lapses occurred more frequently with skilled workers, whereas rule-base mistakes and knowledge-based mistakes occurred more frequently with unskilled workers. Types of accidents Through the analysis of the accident investigation report, lack of working time, ignoring warnings and alarms that help to detect errors, and workers’ inability to concentrate on their work were the causes of action errors. Rule-based mistakes contributed more to chemical accidents than knowledge-based mistakes. Rule-based mistakes was often caused by ignoring warnings and continuous work in hazardous situation as well as misapplication of a good rule The knowledge-based error The knowledge-based error caused a chemical accident due to incorrect and inappropriate information about chemicals as well as lack of experience in the process. Inaccurate understanding of the exact physicochemical properties of hazardous chemicals was investigated as a factor that caused chemical accidents. In addition, some accidents were analyzed in which workers were not familiar with the process control and were unable to handle abnormal dangerous situations. To prevent this type of accident, preparation of procedures for abnormal and emergency scenarios, knowledge and understanding of chemical processes, and organizational learning are necessary. Human Error in Chemical Industry Potential hazards: fires, explosions, toxic leaks. Key role of human error in accidents: 76.1% attributed to human factors. Case Studies (1/2) 3. Explosion During R&D 1. Poisoning by Humidifier Disinfectants Mixing incompatible reactive Misuse of chemicals with unknown chemicals. toxicity. Workers unaware of NFPA reactivity Fatal respiratory damage due to ratings. lack of LC50 data. 2. HF Leakage (2012) 4. Fire from 1,4-Dioxane Lack of proper safety training and Ignition from peroxide-forming emergency response. solvent. Outcome: 5 fatalities, widespread Inadequate risk assessment and MSDS environmental damage. usage. Categories of Human Failure Human Errors: Slips, lapses, and mistakes. Violations: Intentional non-compliance (routine, situational, exceptional). Most accidents involve multiple human failure types. Hierarchy and Causes of Chemical Accidents Root Cause Analysis (RCA):Methods: Flowcharts, FMEA, Bowtie, Fishbone, Pareto charts, FTA, and 5-Whys. RCA identifies interconnected human and process failures. Key Findings: Workers often lack hazard awareness. Education and preventive measures are inadequate. Organizational communication gaps exacerbate risks. Chemical Hazards and Classifications Hazard Classification Frameworks: Globally Harmonized System (GHS): 16 physical, 12 health/environmental categories. NFPA 704 System: Focused on toxicity, flammability, and reactivity. Root Causes of Human Errors Insufficient training on chemical hazards. Poor documentation and understanding of MSDS. Lack of proper safety regulations and their enforcement. Complex and interacting human errors. Preventive Measures Comprehensive and accurate MSDS. Improved education and training for workers. Rigorous risk assessments and work permits. Development of safety culture in organization Root Causes and Prevention Core Issues: Lack of accurate MSDS details and training. Limited field application of safety regulations. Insufficient communication and safety culture. Recommendations: Enhance education and hazard awareness. Implement robust RCA tools universally. Strengthen regulatory compliance and enforcement Conclusion the Human Factors Analysis and Classification System-Petrochemical Enterprise Fire and Explosion (HFACS-PEFE) model is established to examine the mechanism of human failure. The model indicates violations, intellectual limitations, inadequate supervision, and insufficient safety culture are the most important factors in causing the accidents. Both direct causes and latent human failures involved in collected accidents are identified and are then analyzed by experts. To avoid the occurrence of such accidents, direct and indirect measures are proposed to improve human performance Conclusion An accident database is constructed at last by using the Microsoft Excel. The database includes accident date, location, death and injuries. Relationships between different human factors, which are involved in the HFACS-PEFE framework, are identified by conducting chi-square test and odds ratio (OR) analysis. With the help of these relationships different accident development routes and corresponding probabilities are achieved.