Mapping the process and its tasks
Inputs, transformations, products, waste and supporting operations should be identified. The safety data sheet helps identify hazards, but does not necessarily describe every condition of use at a particular installation.
The map must include sampling, cleaning, loading and unloading. A brief operation can generate significant exposure if it opens a system or disperses a product. Observing stable production alone is therefore insufficient.
Distinguishing exposure from process safety
Industrial hygiene examines how agents may reach people. Process safety also considers events such as loss of containment, fires or uncontrolled reactions. The two approaches must inform one another.
HSE notes that a runaway reaction can cause a dangerous rise in pressure. Its conditions require specialist study; the properties of an individual substance are not sufficient to determine the safety of a mixture or an industrial reaction.
Controlling emissions and contact
The selection of measures follows the hierarchy of controls: avoid or substitute where possible, reduce emissions and limit exposure through solutions appropriate to the task. Inhalation, skin contact and accidental ingestion require separate consideration.
The effectiveness of a measure must be checked. Installing extraction without reviewing its use or maintenance can leave exposure uncontrolled. It is also necessary to assess whether the modification introduces other hazards.
Storage and non-routine interventions
Material compatibility, system identification and spill control form part of the review. Cleaning and maintenance tasks require sufficient information about the substances and energy sources present.
Coordination must extend to external companies. Providing a product list does not, on its own, resolve access conditions, equipment preparation or authorisation to begin an intervention.
Managing changes and preparing the response
Management of change must include raw materials, quantities, equipment, software and ways of working. An apparently minor change can alter emissions, reactivity or response capability.
The emergency plan is built around scenarios specific to the installation. Major-accident legislation has its own criteria for application; chemical companies are not all automatically subject to identical obligations simply because of the name of their activity.
Hypothetical example: increasing a batch
A plant proposes increasing a batch size. Before authorising it, competent personnel review the process conditions, equipment capacity, exposures and emergency measures.
The plant documents the decision and adapts instructions and training. It does not assume that a process that is safe at one scale necessarily retains the same conditions at another. HSE technical references must be used alongside the legislation applicable to the establishment.
