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As indicated earlier, OSHA 29 CFR 1910.119, Process Safety Management (PSM) of Highly Hazardous Chemicals is the most prominent standard containing requirements for risk assessment. The Process Safety Management standard was established in 1992 and requires process hazard analyses (PHAs) for regulated industrial processes containing 10 000 pounds or more of a hazardous chemical for the purpose of protecting the employees working in and around such processes. 1910.119(e) requires an initial process hazard analysis (PHA) be conducted and revalidated every five years with a follow‐up PHA. While this requirement is called a process hazard analysis, a PHA is similar to a risk assessment in that it identifies and analyzes the hazards and existing controls to determine if additional controls are needed.

The PHA must be conducted on a prioritized basis and consider the extent of the hazard, number of potentially affected people, age of the process, and operating history of the process. Some of the same risk assessment techniques mentioned in this book and various assessment standards are referenced by the OSHA PSM regulation including those below.

 What‐If Analysis

 Checklists Analysis

 What‐If/Checklists Analysis

 Hazard and Operability Study (HAZOP)

 Failure Mode and Effects Analysis (FMEA)

 Fault Tree Analysis (FTA)

The PHA must address the potential consequences of past incidents and the potential consequences of the failure of engineering and administrative controls. It must also consider human factors and include a qualitative evaluation of safety and health effects of the failure of controls on employees in the workplace. Other notable sections of the Process Safety Management standard include requirements for Pre‐Start‐up Safety Reviews (PSSR) and Management of Change (MOC) procedures.

The references to prioritization and consequences in the PSM regulation are consistent with a risk assessment. All of these PHA activities must be formal and documented. Further discussion can be found on PHAs in Chapter 7, What‐if Hazard Analysis.