Process Safety Management (PSM)

Many of the publications that we offer are to do with the topic of Process Safety Management (PSM), or with related topics such as the offshore Safety and Environmental Management System (SEMS) and Safety Cases. Please refer to the list at the bottom of this page to find articles and safety moments to do with process safety management.

Process Safety Management (PSM) is not new; indeed it has always been an integral part of the process industries. (If it has to have a start date then the explosion at the Flixborough plant in the year 1974 is probably a good choice — which is why the picture at the top of this page is from that disaster.) Companies have always carried out activities such as the writing of procedures, planning for emergencies, training of operators and the investigation of incidents. But it was in the late 1980s and early 1990s that PSM programs became more formalized and regulated. In the United States the key regulation was 29 CFR 1910.119, Process Safety Management of Highly Hazardous Chemicals, from OSHA (the Occupational Safety & Health Administration), introduced in the year 1992. This regulation served as a model for PSM programs in many other nations and for internal programs developed by many large energy and process companies.  During that time companies throughout the world have invested huge amounts of time and money in their process safety programs, including those that are similar in scope and intent but that have different titles, such as SEMS (the offshore Safety and Environmental Management System). Companies have also invested in related programs, particularly the Safety Case approach, which is widely used outside the United States.

The Center for Chemical Process Safety (CCPS 2007b) provides guidance as to what constitutes a PSM event.

  • It must involve a chemical or have chemical process involvement;
  • It must be above a minimum reporting threshold;
  • It must occur at a process location; and
  • The release must be acute, i.e., it must occur over a short period of time.

Inevitably, when a program such as Process Safety Management (PSM) becomes so widespread and has been in use for so long, its meaning can become altered or diluted. So, it is useful occasionally to step back and consider just what PSM is — and, by implication, to consider what it is not. Probably the best way of doing so is to examine each of the words in the phrase: ‘Process’, ‘Safety’ and ‘Management’. But first, it makes sense to consider the historical background to the development of PSM in order to provide the correct context for the discussion.


In the late 1980s various chemical plants in south Texas experienced series of severe explosions and fires. Prior to that, in the year 1984 at the town of Bhopal in India, the world witnessed the worst-ever catastrophe involving the chemical industry. The official death toll for this event was 3,787 — many more people suffered severe and disabling injuries as a result of inhaling the methyl isocyanate gas that had been released. The overall impact of these events was to create a sense that “something must be done”. 

In the United States, the response to this sense of needing to do something was incorporated into the Amendments to the Clean Air Act legislation. It required that OSHA (the Occupational Safety and Health Administration) and the EPA (Environmental Protection Agency) issue regulations to do with process safety. They became OSHA’s Process Safety Management program (29 CFR 1910.11) and the EPA’s Risk Management Program (RMP). They focus on worker safety and public safety respectively. The OSHA standard was issued first (in the year 1992) and has become something of a “go-by” for many other PSM programs, including those prepared by companies for their own internal use.

It is important to understand that neither OSHA nor the EPA actually wrote their respective regulations. Industry executives from various chemical companies recognized that the introduction of a process safety regulation in the United States was inevitable, so they took the initiative. Therefore, senior managers from these companies, working with the Organization of Resource Counselors, set about developing a standard that would meet the need for worker safety, environmental protection and that would really help improve safety — it would not just add another layer of bureaucracy.

Published in 1988, their report was entitled “Recommendations for Process Hazards Management of Substances with Catastrophic Potential.” The document served not only as the basis for the regulations from OSHA and the EPA (in the case of OSHA it was 29 CFR 1910.119) but also the API (American Petroleum Institute) RP 750.

From the beginning, it was understood that process safety standards need to be non-prescriptive and performance based. The companies who drafted the standard were trying to avoid the problem of having a large number of lengthy, highly prescriptive, detailed regulations such as are to be found in the environmental and nuclear power businesses. This was important because there is such a wide variety of processes and technologies, and the development of detailed standards for all of them would have been very time consuming and inefficient.

It is noteworthy that these early standards “worked”. Not only did they help improve safety, they also helped companies improve their overall operations, including production and plant availability. And, by and large, they are still working.

Furthermore, even though there have been steady improvements in the design and implementation of process safety management systems, the original structure, developed all those years ago, has undergone little radical change.


The first word in the phrase ‘Process Safety Management’ tells us that the system is to do with complex chemical and energy industrial processes. PSM is distinct from topics such as Behavior-Based Safety; although the involvement of personnel at all levels is crucial to PSM, these programs are about understanding what are often highly complex process and energy facilities that involve sophisticated technology, the use of sometimes exotic chemicals and systems that involve hard-to-understand feedback loops and multiple-contingency events. This is not easy.

Occupational Safety

The relationship with Occupational/Personal Safety programs is mostly one way. An effective PSM program can help generate improvements in occupational safety issues. For example, a better understanding of the consequences of say high temperature in a vessel cold generate new thoughts to do with PPE (Personal Protective Equipment). However, it is unlikely that the arrow will often point in the other direction.

Other Industries

Although PSM was developed by and for the process industries, its principles and practices can be applied to a broader range of industries — as discussed in Safety Moment #8: But We’re Different, You Know”. PSM principles can even be used in different types of industry, such as Safety Moment #47: Hyperloop Generic Safety Study.

Although these applications of PSM are useful such industries do differ from the process industries in as much they not generally as inherently complex; in particular, they do not have as many feedback loops of energy, process materials and instrumentation signals.


“Safety” is the second word in the term ‘Process Safety Management’. The reason for the development of PSM programs, as just discussed, was to address the safety issues that became so prominent in the 1980s.

Yet, from the beginning, managers and process safety professionals have understood that a well-managed facility will not only be safe, it is more likely to be efficient, productive, reliable and environmentally clean. Many PSM professionals believe that their work actually makes money.

They may be right — although that opinion is difficult to prove.


A fundamental premise of Process Safety Management is that safety — and operations in general — can be managed, i.e., that, in principle, all systems, both technical and human, can be understood rationally, and can be controlled. To put it another way, there is no such thing as luck, nor are there Black Swans (an idea that is, however, challenged somewhat in Safety Moment #11: Black Swans and Bow Ties).

The venerable OSHA standard organized process safety management system into the following 14 elements.

  1. Employee Participation
  2. Process Safety Information
  3. Process Hazards Analysis
  4. Operating Procedures
  5. Training
  6. Contractors
  7. Prestartup Safety Review
  8. Mechanical Integrity
  9. Hot Work
  10. Management of Change
  11. Incident Investigation
  12. Emergency Planning and Response
  13. Compliance Audits
  14. Trade Secrets

Since the publication of this list in the early 1990s other organizations, such as the CCPS (Center for Chemical Process Safety) have developed improved versions. But the striking reality is that the list first prepared by the committee working with Organization of Resource Counselors has held up so well.


Copyright © Ian Sutton. 2018. All Rights Reserved.

The Case for Safety Cases

The Deepwater Horizon/Macondo catastrophe in the Gulf of Mexico (GoM) in the year 2010 demonstrated the need for new safety management regulations. The draft regulations went through various iterations, and the name of the responsible government agency changed twice. In the end, the SEMS (Safety and Environmental Management System) regulation became a requirement for offshore oil and gas operations in the United States.

The Cruise Ship’s Galley

A process safety expert and his wife went on a cruise. Part of the cruise included a tour of the ship’s impressive galley and food-serving facilities. The tour was led by one of the ship’s sous chefs.

The process safety expert realized that he was looking at a small chemical plant. In front of him were processes that involved chemical reactions, heat exchange and moderately high pressures. So he naturally started to ask the sous chef HAZOP-style questions on the following lines.

Q: Do you use natural gas for cooking?

Safety Moment #50: Temporary Change

Management of Change (MOC) lies at the heart of a successful process safety management system. If a facility is properly designed and constructed then virtually all incidents are caused by someone, somewhere making a change and inadvertently taking the process outside its safe limits. This means, therefore, that, in order to have full control of a facility managers and process safety experts must have a clear definition of the word “change”.