Developing Credible Scenarios for a PHA

OSHA’s Compliance Guidelines and Recommendations for the PSM Standard states “A PHA is an organized and systematic effort to identify and analyze the significance of potential hazards associated with the processing or handling of highly hazardous chemicals.” It goes on to say “A PHA is directed toward analyzing potential causes and consequences of fires, explosions, releases of toxic or flammable chemicals and major spills of hazardous chemicals.” OSHA does not give any additional guidance; they just refer you to 18 additional “Sources of Further Information”. So rather than spending your free time reading these books, I would like to present a process on how to develop scenarios (causes and consequences), tips on creating credible and realistic scenarios and the pitfalls to avoid during the process, commonly encountered during a PHA .

What is a “cause”?

Julius Caesar once said “In war, events of importance are the result of trivial causes.” Are we at war? No,  but like war, in our industry, if we do not properly identify or understand the hazards we work with, we are faced with the possibility of fires, explosions and releases of toxic chemicals. So where do we start? By first determining what “causes” can end up leading to a hazardous consequence. The Merriam-Webster Dictionary defines a cause as “something or someone that produces an effect, result, or condition: something or someone that makes something happen or exist”.  We will be reviewing how to identify causes throughout the PHA, focusing on how to identify causes, determining through PHA Team interaction if these causes are credible, some pitfalls to avoid during the process, and tips on how to document these causes.

What is a “consequence”?

Michael Jordan said “I never looked at the consequences of missing a big shot... when you think about the consequences you always think of a negative result.” Unfortunately, when we talk about consequences in our industry we have to do the exact opposite of the philosophy which made Michael Jordan great. OSHA states that the purpose of the PSM Standard is for “…preventing or minimizing the consequences of catastrophic releases…”  Is this the best evaluation approach to take? We will focus on how to determine credible and plausible consequences, pitfalls to avoid when determining consequences, and how to best document these consequences.

So what now?

Ralph Waldo Emerson said “Shallow men believe in luck or in circumstance. Strong men believe in cause and effect.”  Now that we have worked on developing a good scenario, cause and consequence, we will look at some examples of what to expect from good and bad scenarios, to better understand the benefits of spending the time needed to develop credible scenarios.