Controlling dangerous substances depends on people. The explosive atmospheres regulations place clear duties on employers, and every worker has a part to play in keeping fire and explosion risks under control.

This final module covers employer duties, emergency arrangements, training, recording, warning signs, permits to work and hot work, co-ordination between employers, and your own duties.

Under the explosive atmospheres regulations, the employer must:

• Carry out a risk assessment before work with dangerous substances begins.
• Eliminate the risks, or reduce them so far as is reasonably practicable.
• Classify hazardous areas into zones, and use suitable equipment.
• Make arrangements to deal with accidents, incidents and emergencies.
• Provide information, instruction and training.
• Co-ordinate safety measures where employers share a workplace.

The Chemical Agents Regulations require arrangements to deal with accidents, incidents and emergencies, including:

• Written emergency plans and procedures.
• Safety drills, carried out at regular intervals.
• Warning and communication systems, such as visual and audible alarms.
• Escape facilities, where the risk assessment shows they are needed.
• Suitable first-aid facilities.
• Information for the emergency services about the hazards on site.

Employees must receive suitable information, instruction and training, kept up to date when the work changes, on:

• The dangerous substances present, and the risks they pose.
• The significant findings of the risk assessment.
• The control measures, and the zones in their work area.
• How to use equipment and protective equipment correctly.
• What to do in an emergency.
• Where to find the safety data sheets.

Before work begins, the employer must draw up an explosion protection document, and keep it up to date. It shows that the explosion risks have been assessed, which places are classified into zones, and that suitable measures are in place, with equipment designed, used and maintained safely.

It may combine existing risk assessments and other documents. It must be revised whenever the workplace, the equipment or the organisation of the work changes significantly.

Containers and pipes holding dangerous substances must be clearly identified, so that everyone knows what is inside, including during maintenance and in an emergency.

Containers should carry their supplier labels, and decanted substances must be labelled too. Never put a dangerous substance into an unlabelled container, or into a drinks bottle. Pipework should be marked to show what it carries, especially near valves and connection points.

Where necessary, the entry points to places classified into zones must be marked with the EX warning sign. It is a yellow triangle, with black edging, and the black letters E and X.

The sign warns that an explosive atmosphere may be present inside. Only authorised people should enter, with suitable equipment, and without ignition sources such as phones, lighters or ordinary tools.

High-risk work in or near hazardous areas, such as maintenance, breaking into pipework or entering vessels, must be carried out to written instructions and, where needed, under a permit to work issued by a responsible person.

The permit sets out exactly what work is allowed, the hazards, the isolations and gas tests needed, and the precautions to be taken. Work stops if conditions change, and the permit is signed off when the job is complete.

Hot work, such as welding, cutting and grinding, needs a hot work permit.

• Before it starts, the area is checked and gas-tested.
• Flammable materials are removed, or covered with fire-resisting blankets.
• Plant is isolated, and drains and openings are sealed.
• Suitable fire extinguishers are at hand.
• A fire watch continues during and after the work, because materials can smoulder and ignite later.
• The permit is then formally closed.

Where two or more employers share a workplace, for example a site with contractors, the employer responsible for the workplace must co-ordinate the measures needed to protect everyone from dangerous substances.

Each employer remains responsible for the matters under their own control. Contractors must be told about the zones, permits and emergency arrangements on site, and must follow them. The co-ordination arrangements are set out in the explosion protection document.

Under the Safety, Health and Welfare at Work Act 2005, employees must take reasonable care, and co-operate with their employer. In practice, this means:

• Follow safe procedures, permits and instructions.
• Use controls, equipment and protective equipment correctly, and never bypass them.
• Report defects, leaks and spills immediately.
• Never take ignition sources into hazardous areas.
• Take part in training and emergency drills.

If you find a leak or spill of a flammable substance:

• Do not operate switches, phones or anything that could cause a spark.
• Warn others nearby, and keep them away.
• Shut off the source only if you have been trained, and it is safe to do so.
• Raise the alarm, and report it to your supervisor.
• Follow the emergency procedure, and evacuate if instructed.
• Do not return until the area has been declared safe.