Eliminating the risks of hazardous substances must always be considered first.
The most effective way to manage a risk is to completely remove the hazard from your workplace. This means eliminating the creation of hazardous dusts, gases, fumes and vapours. Examples of elimination can include:
- using products or materials that don’t contain the hazardous substance. For example, changing to organic or free-range farming or natural alternatives that don’t use chemical pesticides or herbicides.
- eliminating the need to undertake the task that releases the hazardous substance into the air.
In some cases, elimination might not be reasonably practicable. Where this occurs, you must minimise the risks as far as is reasonably practicable. One way to manage risks of exposure to hazardous substances is by selecting and implementing measures using the hierarchy of controls (Figure 1).
Figure 1. The hierarchy of control measures
Substitution
Substitution controls involve replacing the hazard with something safer. Examples of substitution controls can include:
- using products or materials with lower levels of the hazardous substance. For example, engineered stone can be substituted with a product that contains a lower percentage of crystalline silica
- using tools or equipment that generate lower levels of the hazardous substance. For example, battery operated machinery can be used to reduce exposure to petrol fumes
- using chemicals or materials that generate lower levels of the hazardous substance. For example, herbicides or fertilisers that cause high levels of dust can be replaced with granular or liquid formations
- using ingredients or products that have a stabiliser to minimise fume and vapour production
- replacing high toxicity paints, glues and varnishes with lower toxicity or non-toxic alternatives
- using a product that does not need to be cut, ground or polished
Isolation
Isolation controls involve isolating the hazard from people by placing barriers or distance between a hazard and your workers. Examples of isolation controls can include:
- completing the task that releases the hazardous substance in an enclosed, well ventilated space that is separated from people
- creating physical barriers and exclusion zones around tasks and between workers
- using machinery or vehicles that have an enclosed cabin and keeping doors and windows closed when doing work that generates dusts
- using suitably fitted positive pressure cabins on earthmoving plant
- having a room or area away from the work area for other tasks such as changing or eating
Engineering controls
Engineering controls involve using a physical control measure, such as a mechanical device or process, to change the characteristics of a task. The best engineering controls for your workplace will depend on the tasks your workers carry out. Examples of engineering controls include:
- using wet cutting or water suppression to prevent dusts from being released into the air
- using local exhaust ventilation to remove respiratory hazards from the air
- using tools fitted with local exhaust ventilation or dust extraction systems
- using nozzles that limit spray or droplet size and direction, to avoid the workers’ breathing zone
- automating tasks that generate dusts, gases, fumes and vapours. For example, a hay bale processor or spreader could be used rather than hauling and spreading hay by hand
- using plant that is designed to cut and completely encapsulate dusts, gases, fumes and vapours
- using industrial vacuum cleaners with appropriate filtration during clean up of dust
Administrative controls
If you’ve worked through the hierarchy of control measures and risk remains, you must minimise the risk by implementing administrative controls. Examples of administrative controls include:
- planning tasks to minimise the quantity of the hazardous substance being released into the air
- establishing policies about working with the hazardous substance and clean up requirements
- installing signage alerting people of the risks involved and how to minimise them. For example, a sign alerting workings of silica dust.
- designating change areas for changing out of personal protective equipment or contaminated work clothes
- providing a service to launder contaminated work clothes at work
- implementing shift rotation policies to minimise the time workers spend in an exposure area
- developing policies for storing, cleaning and maintaining equipment
- developing policies and procedures for keeping work areas clean, such as using low pressure water, wet sweeping or a M or H class rated vacuum cleaner
- developing policies and training for workers, including administrative workers, to help them understand and manage workplace risks
Personal protective equipment
Personal protective equipment (PPE), including masks, is the least effective control measure because it does not control the risk at the source. PPE should only be considered after implementing substitution, isolation, engineering, and administrative controls. You should use PPE to supplement higher-level control measures if they do not control the risk fully. It is important to make sure the PPE, including respiratory protective equipment:
- is suitable to protect against the risk
- fits the worker who will be wearing it
- is clean and in good working order
- is stored appropriately
If you have determined that respiratory protective equipment (RPE) or other PPE is required to minimise WHS risks, you must provide it to workers. You must also provide training on using and maintaining it and make sure workers are using it correctly. Depending on the type of RPE, it may have to be fit tested by a competent person such as a certified occupational hygienist.
For further advice and guidance, talk with your state or territory WHS regulator.
More information about managing the risk of occupational disease in the workplace can be found in the Model Code of Practice: How to manage work health and safety risks.