In one line: Identify the hazards, assess the risks, control them in layers, manage every change, and learn from other people’s incidents. In process industries, safety is a leadership responsibility, not a compliance task.
Core idea
Chemical processes handle energy and materials that can harm workers, neighbors, the environment and the business itself. Process safety focuses on preventing the rare, catastrophic events: fires, explosions and toxic releases. It is distinct from personal safety, which deals with slips, trips and cuts. The two need different measures: a plant can have an excellent injury record and still be one valve failure away from disaster.
How it works
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Identify the hazards. Some are physical: pressure, heat, cold, noise, radiation, machinery. Chemical hazards fall into three groups:
- physical hazards: explosives, flammables, oxidizers, compressed gases, corrosives
- health hazards: toxicity, corrosion of the skin, chronic effects
- environmental hazards
Safety data sheets help, but they vary in quality, so check several reputable sources.
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Check compatibility. Chemicals react with one another and with the materials of construction. Corrosion can be slow and invisible. In Flint, Michigan, a change of water source without corrosion control dissolved the protective layer inside old pipes, and lead leached into the drinking water.
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Assess the risk. A risk matrix ranks each scenario by likelihood, from “never heard of in the industry” to “happens several times a year here”, and consequence, from no injury to fatalities and major environmental damage. The highest-risk scenarios get attention first (see Risk Management, Failure Mode and Effects Analysis).
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Control the risk in layers. In order of preference:
- eliminate or substitute the hazard
- design it out, for example with lower inventories or lower pressures
- engineering controls, such as relief valves, interlocks and inert gas
- procedures and training
- personal protective equipment
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Manage change. A large share of incidents follow a change in materials, equipment, procedures or staffing. A formal management of change review asks what new hazards the change creates (see Engineering Change Control).
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Learn from incidents. The chemical engineering community publishes free, one-page monthly lessons for plant workers, the Process Safety Beacon [1]. One example shows how trace amounts of flammable material can build up in a vessel’s vapor space until it becomes explosive. The U.S. Chemical Safety Board publishes detailed investigations and videos of major accidents [2].
In practice
Investigations of major incidents repeatedly find the same pattern:
- warning signs that were normalized
- cost and schedule pressure
- changes made without review
- people who saw a problem but didn’t feel able to stop the work
These are leadership failures more than technical ones, the same ones seen in the Challenger Launch Decision. A culture where anyone can stop the work is built deliberately, through Psychological Safety and visible leadership commitment.
Questions to ask the experts
- What are the worst credible scenarios here, and which layers of protection prevent each one?
- What has changed recently, and was it reviewed?
- What incidents elsewhere involved this kind of process, and what did we learn from them?
Connections
- Tools: Risk Management, Failure Mode and Effects Analysis, Engineering Change Control.
- Culture: Challenger Launch Decision, Psychological Safety. The discipline: Chemical Engineering.
- Capabilities exercised: Ethical Actions and Integrity, Responsibility and Urgency to Deliver, Courage.
Sources
- CCPS, Process Safety Beacon [1]
- U.S. Chemical Safety Board investigations [2]
- Course lecture on process safety; no public source.