Hazards and Risk Factors in Manual Handling
Load, task, individual, environment
Manual handling hazards are not only about weight. Load factors include size, shape, grip, stability, sharp or hot surfaces, and whether the load is animate. Task factors include frequency, duration, distance, bending, twisting, reaching, carrying on stairs and awkward starting or finishing heights. Individual factors include fitness, pregnancy, previous injury, age, height and clothing. Environmental factors include floor condition, lighting, space, doors, steps, temperature and obstructions.
Worked example
Workers unload boxes from a van. The boxes weigh 12 kg - acceptable to many people - but they are stacked above shoulder height, the van floor is slippery, and each box must be twisted and carried 20 m. The weight alone would miss the real risk. The assessment should address the stack height, the floor, the carry distance and the twisting, perhaps with a conveyor or a height-adjustable platform.
Why it matters
The same load can be low risk in one setting and high risk in another. Risk factors interact: a moderate load lifted frequently with a poor grip and a twisted trunk is more hazardous than a heavier load lifted once with a good grip and a clear route. Psychosocial factors such as time pressure and lack of control can also increase risky behaviour, although they do not replace physical risk assessment.
Traps
Do not reduce the assessment to a weight limit. Do not blame the worker's technique when the real problem is task design. Do not ignore frequency and duration. Do not forget the route and the destination, not just the lift itself.