FactSheet The Importance of Root Cause Analysis During Incident Investigation The Occupational and Administration (OSHA) and the Environmental Protection Agency (EPA) urge employers (owners and operators) to conduct a root cause analysis following an incident or near miss at a facility.1 A root cause is a fundamental, underlying, system-related reason why an incident occurred that identifies one or more correctable system failures.2 By conducting a root cause analysis and addressing root causes, an employer may be able to substantially or completely prevent the same or a similar incident from recurring.

OSHA Process Safety Management An employer conducting a root cause analysis and EPA Program to determine whether there are systemic reasons Requirements for an incident should ask: Employers covered by OSHA’s Process Safety – Why was the oil on the floor in the first place? Management (PSM) standard are required – Were there changes in conditions, processes, to investigate incidents that resulted in, or or the environment? could reasonably have resulted in, catastrophic – What is the source of the oil? releases of highly hazardous chemicals.3 – What tasks were underway when the oil Similarly, owners or operators of facilities was spilled? regulated under EPA’s Risk Management – Why did the oil remain on the floor? Program (RMP) regulations must conduct – Why was it not cleaned up? incident investigations.4 – How long had it been there? During an incident investigation, an employer – Was the spill reported?6 must determine which factors contributed to It is important to consider all possible “what,” the incident, and both OSHA and the EPA “why,” and “how” questions to discover the root encourage employers to go beyond the minimum cause(s) of an incident. investigation required and conduct a root cause analysis. A root cause analysis allows an In this case, a root cause analysis may have employer to discover the underlying or systemic, revealed that the root cause of the spill was a rather than the generalized or immediate, causes failure to have an effective mechanical integrity of an incident. Correcting only an immediate program—that includes inspection and repair— cause may eliminate a symptom of a problem, that would prevent or detect oil leaks. In contrast, but not the problem itself. an analysis that focused only on the immediate cause (failure to clean up the spill) would not have How to Conduct a Root Cause Analysis prevented future incidents because there was no A successful root cause analysis identifies all system to prevent, identify, and correct leaks. root causes—there are often more than one. Properly framing and conducting a root cause Consider the following example: A worker slips investigation is important for a PSM or RMP- on a puddle of oil on the plant floor and falls. related incident. Take, for example, an incident A traditional investigation may find the cause involving an overfill and subsequent leak of to be “oil spilled on the floor” with the remedy hydrocarbons from a relief valve system that limited to cleaning up the spill and instructing ignites and kills multiple workers. Prior to this the worker to be more careful.5 A root cause fatal incident, there were multiple flammable analysis would reveal that the oil on the floor releases from the relief valve system, but none was merely a symptom of a more basic, or ignited. The employer previously performed fundamental problem in the workplace. incident investigations on the non-lethal inci- Root Cause Analysis Tools dents and determined that operator error was Below is a list of tools that may be used by the cause of the overfills and subsequent leaks. employers to conduct a root cause analysis. However, a proper root cause investigation The tools are not meant to be used exclusively. would have looked deeper into the incident, and Ideally, a combination of tools will be used. determined that funding cuts—which resulted in a deficient mechanical integrity program • Brainstorming and malfunctioning instrumentation—led to • Checklists a dangerous situation that operators could not • Logic/Event Trees have prevented. Had these root causes been • Timelines previously identified, the employer could have • Sequence Diagrams taken action to improve the mechanical integrity • Causal Factor Determination program and repair the instrumentation system, For simpler incidents, brainstorming and preventing the fatal incident. checklists may be sufficient to identify root causes. For more complicated incidents, Benefits of Root Cause Analysis logic/event trees should also be considered. for Employers Timelines, sequence diagrams, and causal Conducting a thorough investigation that factor identification are often used to support identifies root causes will help to prevent the logic/event tree tool. similar events from happening again. In this way, employers will reduce the risk of death Regardless of the combination of tools chosen, and/or injury to workers or the community or employers should use these tools to answer four environmental damage. important questions: By using root cause analysis to prevent similar • What happened; events, employers can avoid unnecessary • How did it happen; costs resulting from business interruption, • Why it happened; and emergency response and clean-up, increased • What needs to be corrected. regulation, audits, inspections, and OSHA or EPA Interviews and review of documents, such as fines. Regulatory fines can become costly, but maintenance logs, can be used to help answer litigation costs can often substantially exceed these questions. Involving employees in the root OSHA and EPA fines. Employers may find that cause investigative process, and sharing the they are spending money to correct immediate results of those investigations, will also go a long causes of incidents that could have been way toward preventing future similar incidents. prevented, or reduced in severity or frequency, by identifying and correcting the underlying OSHA and EPA encourage employers to consult system management failure. the resources below for more information about how to use these tools. Finally, when an employer focuses on prevention by using root cause analysis, public trust can Resources be earned. Employers with an incident free • The Guidelines for Investigating Chemical record may be more likely to attract and retain Process Incidents, Center for Chemical high performing staff. A robust process safety Process Safety, 2nd Edition, 2003. program, which includes root cause analysis, can • DOE Guideline-Root Cause Analysis Guidance also result in more effective control of hazards, Document, U.S. Department of Energy, improved process reliability, increased revenues, Washington, DC, February 1992. http://energy. decreased production costs, lower maintenance gov/sites/prod/files/2013/07/f2/nst1004.pdf costs, and lower insurance premiums. • DOE Handbook- and Operational Safety Analysis, Volume I: Accident Analysis Techniques, July 2012, pp. 2-40–2-86. http:// energy.gov/sites/prod/files/2013/09/f2/DOE- HDBK-1208-2012_VOL1_update_1.pdf • Quality Basics-Root Cause Analysis for • Root Cause Analysis, Washington State Beginners, James L. Rooney and Lee N. Department of Enterprise Services, Olympia, Vanden Heuvel, Quality Progress, July 2004, WA, 2016. www.des.wa.gov/services/Risk/ pp. 45–53. https://www.env.nm.gov/aqb/ AboutRM/enterpriseRiskManagement/Pages/ Proposed_Regs/Part_7_Excess_Emissions/ rootCauseAnalysis.aspx. This resource NMED_Exhibit_18-Root_Cause_Analysis_for_ describes additional root cause tools and Beginners.pdf training opportunities. • Incident [Accident] Investigations, A Guide • How to Conduct an Incident Investigation, for Employers, A Systems Approach to National Safety Council, 2014. http://www. Help Prevent Injuries and Illnesses, U.S. nsc.org/JSEWorkplaceDocuments/How-To- Department of Labor, Occupational Health Conduct-An-Incident-Investigation.pdf and Safety Administration (OSHA), December • Accident Investigation Basics, Washington 2015. www.osha.gov/dte/IncInvGuide4Empl_ State Department of Labor & Industries, Dec2015.pdf 2009. http://www.lni.wa.gov/safety/ • OSHA’s Incident Investigation Topics Page. trainingprevention/online/courseinfo.asp? www.osha.gov/dcsp/products/topics/ P_ID=145 incidentinvestigation • NFPA 921: Guide for Fire and Explosion • OSHA’s On-site Consultation Program offers Investigations. http://www.nfpa.org/codes- free and confidential occupational safety and-standards/all-codes-and-standards/list-of- and health services to small and medium- codes-and-standards?mode=code&code=921 sized businesses in all states and several territories, with priority given to high-hazard 1 The statements in this document are intended as worksites. On-site consultation services are guidance only. This document does not substitute separate from enforcement and do not result for EPA and OSHA statutes or regulations, nor is in penalties or citations. To locate the OSHA it a regulation itself. It cannot and does not impose On-Site Consultation Program nearest you, legally binding requirements on the agencies, call 1-800-321-6742 (OSHA) or visit www.osha. states, or the regulated community, and the gov/dcsp/smallbusiness/index.html measures it describes may not apply to a given • The Business Case for Process Safety, 2nd ed., situation based upon the specific circumstances Center for Chemical Process Safety, 2006. involved. This guidance does not represent final www.aiche.org/ccps/documents/business- agency action and may change in the future. 2 case-process-safety. This resource describes Guidelines for Investigating Chemical Process Incidents, Center for Chemical Process Safety, how a strong PSM program has helped 2nd ed., p. 179. businesses succeed. 3 29 CFR 1910.119. • Mini Guide to Root Cause Analysis, Geoff 4 40 CFR 68. Vorley, Quality Management and Training 5 Guidelines for Investigating Chemical Process Limited, Guilford, Surrey, UK, 2008. www. Incidents, Center for Chemical Process Safety, root-cause-analysis.co.uk/images/Green%20 2nd ed., p. 180. RCA%20mini%20guide%20v5%20small.pdf 6 Id.

This is one in a series of informational fact sheets highlighting OSHA programs, policies, or standards. It does not impose any new compliance requirements. For a comprehensive list of compliance requirements of OSHA standards or regulations, refer to Title 29 of the Code of Federal Regulations. This information will be made available to sensory-impaired individuals upon request. The voice phone is (202) 693-1999; teletypewriter (TTY) number: (877) 889-5627.

DOC FS-3895 10/2016