Incident investigation hazardous conditions

The SSHA evaluates hazardous conditions, on the subsystem level, which may affect the safe operation of the entire system. In the performance of the SSHA, it is prudent to examine previous analyses that may have been performed such as the preliminary hazard analysis (PHA) and the failure mode and effect analysis (FMEA). Ideally, the SSHA is conducted during the design phase and/or the production phase, as shown in Chapter 3, Figure 3.4. However, as discussed in the example above, an SSHA can also be done during the operation phase, as required, to assist in the identification of hazardous conditions and the analysis of specific subsystems and/or components. In the event of an actual accident or incident investigation, the completed SSHA can be used to assist in the development of a fault tree analysis by providing data on possible contributing fault factors located at the subsystem or component level. 

In addition, incident investigations help to identify hazards that either may have been missed earlier or may have slipped out of control during the normal process. It is useful only when conducted with the aim of identifying contributing factors to the incident, condition, and/or activity and preventing future occurrences [5]. 

Recommended preventive actions should make it very difficult, if not impossible, for the incident to recur. The investigative report should list all the ways to foolproof the condition or activity. Considerations of cost or engineering should not enter in at this stage. The primary purpose of incident investigations is to prevent future occurrences. Beyond this immediate purpose, the information obtained through the investigation should be used to update and revise the inventory of hazards, and/or the program for hazard prevention and control. For example, the Job Safety Analysis should be revised and employees retrained to the extent that it fully refiects the recommendations made by an incident report. Implications from the root causes of the accident need to be analyzed for their impact on all other operations and procedures [6]. 

When incidents are investigated (analyzed for cause, not blame) it s important that the investigator uncover the root causes that represent the underlying system weaknesses. Hazardous conditions and unsafe behaviors are called the surface causes for the incident. 

The employer must carry out an initial assessment and then reassess as often thereafter as necessary to ensure compliance. Reassessment should be done at least every two years. When safety and health information or a change in workplace conditions indicates that a new or increased hazard may be present, the employer should also conduct a reassessment. The employer should investigate each work-related death, serious injury or illness, or incident (near-miss) having the potential to cause death or serious physical harm. The employer should keep records of the hazards identified, their assessment, and the actions the employer has taken, or plans to take. 

Gather evidence from many sources during an investigation. Get information from witnesses and reports and observation. Get copies of all reports (documents containing normal operating procedures, flow diagrams, etc., maintenance charts, or reports of difficulties or abnormalities). Keep complete and accurate notes. Record pre-incident conditions, the incident sequence, and post-incident conditions. In addition, document the location of employee, witnesses, equipment, energy sources, and hazardous materials. 

In 1990, the US Clean Air Act authorized the creation of an independent Chemical Safety and Hazard Investigation Board (CSB), but it did not become operational until 1998. Its role, as defined by 40 CFR Part 1600, is to solely investigate chemical incidents to determine the facts, conditions, and circumstances which led up to the event and to identify the cause, probable cause or causes so that similar chemical incidents might be prevented. Its mandate is significantly different than a regulatory enforcement body, as it does not limit the investigation to only determine if there was a violation of an enforceable requirement, but to determine the cause or the causes of an incident. An assumption stated in the overview for the CSB is that it estimated that annually there would be 330 catastrophic incidents and of these, between 10 and 15 would be major catastrophic incidents with life loss. This is an alarming prediction for the industry and clearly indicates some improvement is needed. 

Provide for regular site safety and health inspeetions, to identify new or previously missed hazards and feilures in hazard controls. So that employee insight and experience in safety and health proteetion may be utilized and employee concerns may be addressed, provide a reliable system where employees, without fear of reprisal, may notify managemenf personnel about conditions that appear hazardous and receive timely and appropriate responses and encourage employees to use the system. Provide for investigation of accidents and near-miss incidents, to identify both their causes and means for their prevention. Analyze injury and illness trends over time, so that patterns with common causes can be identified and prevented. 

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