7.4 Control Measures

The need to prevent exposure or, where that is not reasonably practicable, to control it adequately

Employers must make an effort to prevent exposure to hazardous substances where it is reasonably practicable. This may be done by:

• changing the process or activity so that the hazardous substance is not needed or produced
• replacing the substance with a safer alternative
• using it in a safer form, for example pellets instead of powder

The HSE booklet Seven steps to successful substitution of hazardous substances advises on replacing hazardous substances with safer ones.

If prevention is not reasonably practicable, exposure must be controlled adequately. Adequate control means:

• applying the principles of good practice
• not exceeding the workplace exposure limit (WEL) for the substance, if there is one
• if the substance causes cancer, heritable genetic damage or asthma, reducing exposure to as low a level as is reasonably practicable

The principles of good practice must all be applied to get effective and reliable control. They overlap in use and are not ranked, so the first is no more important than the last, although there is a logic in the order in which they appear.

1. Minimise emission, release and spread. Design and operate processes and activities to minimise the emission, release and spread of hazardous substances.
2. Consider all routes of exposure. Take account of inhalation, skin and ingestion when developing control measures.
3. Choose control measures proportionate to the risk. Control exposure by measures that match the health risk.
4. Choose effective control options. Choose the most effective and reliable options that minimise the escape and spread of hazardous substances.
5. Use personal protective equipment as the final option. Where other means cannot achieve adequate control, provide suitable PPE in combination with other control measures.
6. Review the effectiveness of controls. Check and review every element of the controls regularly for continuing effectiveness.
7. Provide information and training. Inform and train all employees about the hazards and risks of the substances they work with and the use of the control measures.
8. New measures, new risks. Make sure that bringing in controls does not increase the overall risk to health and safety.

Put in place measures that suit the activity and agree with the risk assessment, including, in order of priority, one or more of the following:

• appropriate work processes, systems and engineering controls, and suitable work equipment and materials, for example processes that minimise the amount of material used or produced, or equipment that totally encloses the process
• control of exposure at source, for example local exhaust ventilation, and reduction to a minimum of the number of employees exposed, the level and duration of exposure, and the quantity of hazardous substances used or produced in the workplace
• personal protective equipment such as face masks, respirators and protective clothing, but only as a last resort and never as a replacement for other controls that are required

Summary notes for Element 7 · Cheat sheet · Glossary. A study aid, not published or endorsed by NEBOSH.