Article by Workplace Health and Safety Queensland
In August 2020, a worker suffered a chest laceration when the angle grinder he was using ‘kicked back’. At the time, he was apparently cutting timber and fibre glass with a 125mm angle grinder fitted with a multi-cutter blade.
In a separate incident two months later, a young apprentice suffered serious injuries to his groin, right leg and stomach when a 9-inch angle grinder he was using kicked back and struck him. It appears he was cleaning a steel beam.
IMPORTANT: These findings are not yet confirmed and investigations are continuing into the exact cause of both incidents.
Preventing a similar incident
Serious incidents can occur when cutting and grinding discs are fitted onto hand-held power and air tools. Common injuries include amputated fingers, severed tendons and deep cuts to the face, upper body or legs.
Multi-cutters are tungsten tipped saw blades that were originally designed to be used on small power saws, not angle grinders. Injuries from multi-cutters on angle grinders are more serious than those associated with conventional fibre re-enforced cutting discs, because:
- multi-cutters cut through materials at a faster rate
- multi-cutters are more prone to jamming and kickback
- the tungsten tips are sharper and generally cause a wider, deeper, and longer wound
- the tungsten cutting tips can fly off the blade at high speed when the multi-cutter is used as a grinding tool due to the side loading applied to the blade.
When using power tools or air tools fitted with a disc or blade, ensure:
- multi-cutter blades are only used on suitable power tools in accordance with the manufacturer’s instructions
- the rated speed marked on the disc or blade must not be less than the rated speed marked on the power tool
- the size of the cutting disc must not exceed that specified by the power tool manufacturer
- workers hold hand power tools with both hands as specified by the manufacturer
- operators stand with both feet on a level surface that is not slippery and use the tool in front of the body
- heavy and powerful tools are not used above chest height.
Work Health and Safety (WHS) legislation imposes duties on designers, manufacturers, importers and suppliers to ensure plant such as multi-cutters and angle grinders are, so far as is reasonably practicable, without risk to health and safety. Duty holders must ensure the provision and maintenance of safe plant such as angle grinders. Effective risk management starts with a commitment to health and safety from those who operate and manage the business or undertaking.
Managing WHS risks is an ongoing process. Risk management involves four steps:
- Identify hazards – find out what could cause harm
- Assess risks – understand the nature of the harm that could be caused by the hazard, how serious the harm could be, and the likelihood of it happening
- Control risks – implement the most effective control measures reasonably practicable in the circumstances
- Review control measures – to ensure they are working as planned.
Control measures are ranked from the highest level of protection and reliability to the lowest and are known as the hierarchy of control. Duty holders must work through this hierarchy to choose the controls which most effectively eliminate or, where this is not reasonably practicable, minimise the risks.
Risk control measures can include:
- Substitution – before using an angle grinder, assess the risks and consider whether an angle grinder is the right tool for the task or whether there is another tool more suitable saw for cutting (e.g. a circular saw or bench mounted). Additionally, ensure the disc or blade selected is appropriate for the task (i.e. only use a cutting disc for cutting and grinding disc for grinding). The disc should include information about the type of power or air tool it can be attached to.
- Engineering – consider whether modifications to the power tool will improve safety if a multi-cutter is attached. Examples include –
- fitting full spring-loaded guarding on angle grinders fitted with multi-cutters
- providing guards on all power tools where there is a risk of the disc ejecting, disintegrating or cutting the worker.
- Administrative controls – if risk remains, it must be further minimised by implementing administrative controls, for example:
- regular maintenance and inspection of the grinder and cutting disc by a competent person, according to the manufacturer’s specifications (for example, ensuing the centre nut securing the multi-cutter blade is regularly checked for tightness)
- providing operators with appropriate information, training and instruction to ensure the grinder is operated safely and competently
- exclusion zones are set up around workers so other people cannot be injured if the worker loses control of the equipment, the disc disintegrates or is ejected.
- Personal protective equipment (PPE): Any remaining risk must be minimised with suitable PPE, for example:
- workers must not wear loose clothing or jewellery and must securely tie back long hair so they cannot become caught in a moving part of the tool
- workers who wear protective clothing such as safety glasses, leather aprons, gloves, face shield (if required), safety boots and hearing protection will be better protected.
In addition to the hierarchy of control, all operators of plant and machinery should follow the manufacturer’s instructions for safe operation.
The control measures you put in place should be reviewed regularly to make sure they work as planned.
- How to manage work health and safety risks Code of Practice 2011 (pdf)
- Managing risks of plant in the workplace Code of Practice 2013 (pdf)
- WHS Alert – Multi-cutters and other discs on power tools and air tools
- WHS Alert Guards and discs on angle grinders