Most jobs in the workforce involve carrying out manual tasks in some shape, way or form. A hazardous manual task is where you engage in a process that puts your body at risk of suffering an injury.
Examples of manual tasks include stacking shelves, working on a conveyor line or sitting at a computer. Some manual tasks are hazardous and can cause serious injury like musculoskeletal disorders. Tasks do not necessarily need to involve any external force. Even your own body weight in an abnormal or sustained posture may be risky.
Hazardous manual tasks include using the body to lift, lower, push, pull, carry or otherwise move, hold or restrain any object, person or animal and involves one or more of the following:
- repetitive or sustained force
- high or sudden force
- repetitive movement
- sustained or awkward posture
- exposure to vibration.
The Hazardous manual tasks – Code of Practice provides further information on how to identify hazardous manual tasks and control the risks of workers being affected by musculoskeletal disorders.
A musculoskeletal disorder means an injury to, or a disease of, the musculoskeletal system, whether occurring suddenly or over time.
It can be:
- a back injury
- a sprain or strained muscle
- torn ligament or tendon
- degeneration of a joint or bone
- nerve damage such as carpal tunnel syndrome.
These ailments can all result from poorly managed hazardous manual tasks.
There are seven groups of contributing factors that to some extent affect all workplaces, including:
- individual factors
- psychosocial factors
- work organisation
- work layout and awkward postures
- load and forceful movements
- task invariability
- environmental issues.
These factors combine in a way that magnifies their effect. By only addressing one or two factors and not all of them, you are unlikely to achieve the goal in preventing injury.
Under our state's work health and safety (WHS) laws, certain people (called duty holders) in a workplace have specific duties:
- a person conducting a business or undertaking
- have the primary duty of care to ensure, so far as is reasonably practicable, that workers and other persons are not exposed to health and safety risks arising from their business or undertaking
- designers, manufacturers, importers and suppliers of plant and structures
- must ensure, so far as is reasonably practicable, that the plant or structure they design, manufacture, import or supply is without risks to health and safety.
- officers, such as company directors
- must exercise due diligence to ensure that the business or undertaking complies with the WHS Act and Regulations and take reasonable steps to ensure that appropriate resources and processes are used to eliminate or minimise risks that arise from hazardous manual tasks.
- must take reasonable care of their own health and safety and ensure they don't adversely affect the health and safety of anyone else.
To manage the risks associated with hazardous manual tasks, a duty holder must follow a risk management process to:
- identify hazards which could give rise to a risk
- eliminate the risk, so far as is reasonably practicable
- minimise the risk by implementing control measures in accordance with the hierarchy of control, if it is not reasonably practicable to eliminate the risk
- maintain the control measure so that it remains effective
- review risk control measures.
Refer to Appendix A of the Code of Practice for an overview of the risk management process.
Static loading refers to physical exertion in which the same posture or position is held throughout the exertion. These types of exertions put increased loads or forces on the muscles and tendons, which contributes to fatigue. This occurs because not moving impedes the flow of blood that is needed to bring nutrients to the muscles and to carry away the waste products of muscle metabolism. Examples of static postures include gripping tools that cannot be put down, holding the arms out or up to perform tasks, or standing in one place for prolonged periods.
Some principles of motion-economy that reduce the range of physical movement are now recognised as hazardous due to their effect on increasing static work at the expense of healthy dynamic movement.
Sedentary work poses a real threat to worker safety and is linked to a range of health problems including:
- musculoskeletal disorders
- cardiovascular disease
- poor mental health
- some cancers
- premature death.
The negative health effects from prolonged sitting are due to:
- insufficient movement and muscle activity
- low energy expenditure
- not moving enough
- not changing posture enough.
General task rotation, combined with a mixture of sitting, standing and movement throughout your day, is the best way to reduce the impact of sedentary work.
Identifying hazardous manual tasks
There are several ways you can be on the lookout for hazardous manual tasks, including:
- consulting your workers who are affected, or likely to be affected, by a manual task, as they will provide valuable information about discomfort, muscular aches and pains which can signal potential hazards
- reviewing available information such as records of workplace injuries and accidents, inspection reports and work injury insurance claims, as they can help identify which manual tasks may cause harm
- observing trends which may show certain tasks have more characteristics which make them hazardous.
This will help the decision process in determining which manual task hazards should be addressed as a priority.
Assessing the risks
Conducting a risk assessment is the best way to examine in more detail the traits of a particular hazardous manual task you have identified as being dangerous, unless the risk is well known and you know how to control it.
A risk assessment will help you determine:
- which postures, movements (or lack of movement) and forces of a task pose a risk
- where they pose a risk during the task
- why they are occurring
- what needs to be fixed.
Determining the risk factors
The following questions can help you determine which postures, movements and forces of a task pose a risk.
Question 1: Does the task involve any of the following:
- repetitive movement?
- sustained or awkward postures?
- repetitive or sustained forces?
- mental stress / tension?
The term ‘repetitive’ means that a movement or force is performed more than twice a minute, while ‘sustained’ means a posture or force is held for more than 30 seconds at a time.
Question 2: Does the task occur over a long time?
If a ‘yes’ response is given to Question 1, then the time taken to complete the task should be determined.
If the task is done for more than 2 hours over a whole shift, or continuously for more than 30 minutes at a time, there is a risk of musculoskeletal disorders.
Question 3: Does the task involve high or sudden force?
Force is the amount of muscular effort required to perform, attempt to perform, resist or change a movement. Forceful muscular exertions can overload muscles, tendons, joints and discs, and are associated with most musculoskeletal disorders.
High force is exerted when large loads, relative to the body part doing the activity, are placed on muscles and other tissues. An indicator of a high force is when a worker describes a task as physically demanding, needs help to do it, requires a stronger person or two people to do the task, or where a normally one-handed task requires two hands.
Sudden force occurs when there is a rapid increase or decrease in muscular effort. Examples of sudden force include jarring, jerky or unexpected movements. It is particularly hazardous because the body must suddenly adapt to the changing force. Tasks which include sudden force typically generate high force as well. Accelerating too fast when applying force, or trying to catch a falling load, can create sudden hazardous forces.
Question 4: Does the task involve vibration?
Prolonged exposure to the whole body or hand-arm vibration increases the risk of musculoskeletal disorders and other health problems. The degree of risk increases as the duration of exposure increases and when the amplitude of vibration is high. Examples of tasks involving vibrations include the use of hand-powered tools or operating a mobile plant.
Is there a risk?
The task involves a risk of musculoskeletal disorders if you have answered ‘yes’ to either:
- Question 1 and Question 2, or
- Question 3
If you answered ‘yes’ to Question 4, the task may be a risk but requires further investigation.
A task may involve more than one risk factor. The more risk factors that are present, the higher the risk of musculoskeletal disorders.
If you identify a risk, you need to think about the sources of these risks that are present in the task as you may be able to change these to eliminate or reduce the risk of musculoskeletal disorders.
The main sources of risk are:
- work area design and layout
- the nature, size, weight or number of things handled
- systems of work
- the environment.
Controlling the risk
Duty holders must work through the hierarchy of control to choose the control that most effectively eliminates or minimises the risk. This can either involve a single control measure or a combination of two or more different controls.
Eliminating the risk is the most effective control measure and involves eradicating the hazardous manual task along with its associated risk. However, if it isn’t reasonably practicable to eliminate the risk, then you must minimise the risks as much as possible.
|Hierarchy of control||Examples of control measures|
For the most effective controls:
- start at the top of the hierarchy of control
- enable workers to test controls and give their feedback before decisions are made to make them permanent
- develop work procedures to ensure that controls are understood and responsibilities are clear
- communicate the reasons for the change to workers and others
- ensure that any equipment used in the manual task is properly maintained
- provide training to ensure workers can proficiently implement the risk controls, including information about manual tasks risk management, specific manual task risks and how to control them, use of mechanical aids, tools, equipment and safe work procedures and how to report a problem or maintenance issue.
Training as a control method to reduce risk of musculoskeletal disorder is not effective. It is more effective to provide workers with training in:
- how to identify hazards and risks
- strategies to avoid hazards and prevent injury
- how to report hazards and risks they might encounter
- develop controls to address hazards and risks.
Review control measures
Control measures that have been implemented should be reviewed and, if necessary, revised to make sure they work as planned while maintaining a work environment that is without risk to health and safety.
You should review control measures:
- when the control measure is no longer effective
- before a change is made that is likely to give rise to a new or different risk
- if a new hazard is identified
- if consultation indicates a review is necessary
- if a health and safety representative requests a review.
- Work Health and Safety Regulations 2012 (SA) (Chapter 4, Part 2 - Hazardous manual tasks)
- Hazardous manual tasks: Minimising the risk of musculoskeletal disorders - Poster
- Hazardous manual tasks - Risk assessment worksheet