Hazard: Hazardous substances
A hazardous substance is any substance that could cause harm – for example, a substance may be:
- highly flammable or explosive
- toxic
- harmful to the environment
- harmful to health
Forms of hazardous substances
Hazardous substances come in many forms, including:
- chemicals, for example used in cleaning
- fumes, for example those given off in welding or hit cutting processes
- dusts, for example, created when asbestos is removed
- vapours, for example when petrol is spilled
- mists, for example, flammable aerosols
- gases, for example, carbon monoxide
- biological agents, for example, bacteria, viruses or fungal spores
Routes of entry
There are a number of ways in which hazardous substances can enter the body, these are called routes of entry.
The use of hazardous substances may lead to a range of health problems, including burns, dermatitis, asthma and infectious diseases.
It is important to identify substances that could cause harm.
Purchased substances must be in their original containers and have safety labels and safety information.
Containers holding hazardous substances must display hazard pictograms – diamond shaped with a distinctive red border and a black image on a white background – on the label. The pictograms will tell you what type of harm could be caused by the substance.
Safety data sheets provided by the manufacturer will give details of the effects of the hazardous substance and relevant controls.
Control: Hazardous substances
Employers must assess the risks from all hazardous substances used or created.
The person carrying out the risk assessment must have the necessary legal and technical knowledge as well as access to the correct information. In some cases, this may mean obtaining specialist expertise.
The assessor should read the supplier’s safety data sheet and consider issues, such as:
- how hazardous the substance is
- how it is used
- how much is used
- how often it is used
- whether levels in the workplace exceed critical limits
The risk assessment should be reviewed at regular intervals and/or when changes are made to tasks, processes or substances used.
Exposure should be prevented whenever possible by avoiding the need for, or the production of, hazardous substances (elimination).
Choosing a less hazardous substance (substitution) is the next best option.
When elimination and substitution are not possible, the risks can be controlled by:
- isolating or enclosing a process or using local and general ventilation (engineering controls)
- using safe systems of work, good housekeeping, reducing exposure by restricting time and/or the number of people involved in a handling the substance (administrative controls)
- using suitable PPE – such as goggles, masks, gloves, breathing apparatus
Always:
- follow safe working procedures
- use the correct PPE
- report any defects or operational problems, such as poor ventilation
- keep your workplace clean and tidy
- store chemicals in a secure area
- report any symptoms of ill health immediately
Never:
- mix different chemicals together unless authorised
- decant hazardous substances to unlabelled or incorrectly-labelled containers
- use hazardous substances you are not trained and authorised to use
All workers should be given information and training about the hazards and the risks, how these can be controlled and what action to take in an emergency.
By following safe working procedures, injury and illness can be prevented.
The controls chosen must be checked regularly to make sure that they are working. In some cases, the levels of hazardous substances in the air must be monitored.
Staff working with some hazardous substances need regular health checks, for example, to check the skin for dermatitis or the functioning of the lungs.