DSEAR requires a specific risk assessment of any work involving dangerous substances. It identifies the fire and explosion hazards, who is at risk, and the measures needed to control and mitigate them.

This module explains what the assessment must cover, who should carry it out, how it is recorded and reviewed, and how it leads to the controls and zones in your workplace.

Before any work involving a dangerous substance begins, the employer must carry out a suitable and sufficient assessment of the fire and explosion risks. New work must not start until this is done.

The purpose is to find out what could go wrong, how likely it is, how serious it would be, and what must be done to prevent it, or to reduce the harm. Waiting for an accident to show where the risks are is never acceptable.

The assessment must take account of:

• The hazardous properties of each substance.
• The amounts used or stored, and how they are handled.
• The work processes, and how substances could be released.
• Possible ignition sources, including static electricity.
• The likely scale of the effects of a fire or explosion.
• Places connected to the work area by openings, such as drains, ducts and pits.

It is not enough to look only at normal operation. The assessment must also consider:

• Starting up and shutting down equipment.
• Cleaning, maintenance and repair, when equipment is opened up.
• Foreseeable faults, leaks, spills and overfilling.
• How different substances, processes and equipment could interact.
• The safety information in each safety data sheet.

Many serious incidents happen during maintenance, rather than normal running.

The assessment must be carried out by a competent person: someone with the knowledge, training and experience to understand the substances, the process and the controls.

For more complex situations, specialist advice may be needed, for example to classify hazardous areas into zones, or to assess the explosion risk from dusts.

Employees who do the work should be involved, because they know how the job is really done.

Where five or more people are employed, DSEAR requires the significant findings of the risk assessment to be recorded.

The record must include the measures taken to eliminate or reduce the risks, and the classification of any hazardous areas into zones. Where explosive atmospheres may occur, it must also show that equipment and working arrangements are safe.

The assessment is a working document, not a one-off. It must be reviewed regularly, and whenever there is reason to think it is no longer valid. For example:

• A new substance, or a change of supplier or formulation.
• A change to the process, the equipment or the building.
• An increase in the amounts stored or used.
• After an accident, an incident or a near miss.

The assessment drives everything that follows:

• Removing or reducing the dangerous substance.
• Preventing explosive atmospheres from forming.
• Controlling ignition sources.
• Classifying hazardous areas into zones, and choosing suitable equipment.
• Mitigation measures, in case something still goes wrong.
• Emergency arrangements, information and training.

It links each hazard to the specific controls in place.

A small vehicle body shop uses solvent-based paints. The assessment finds that the spray booth and the paint mixing room may contain explosive vapour.

The controls include switching to water-based paints where possible, keeping the booth extraction running, storing paint in a fire-resisting cabinet, using suitable electrical equipment inside the booth and mixing room, earthing the spray gun and booth, banning smoking, and training staff in spill and fire procedures.

As an employee, you play an important part:

• Tell the assessor how the work is really done, including any short cuts.
• Point out leaks, spills, dust build-up or ignition sources you have noticed.
• Report changes, such as new products or equipment, so that the assessment can be reviewed.
• Make sure you understand the findings that apply to your work.