There are situations where a worker may be accidentally exposed to superficial cuts and grazes.
There are also repetitive circumstances (like working while kneeling) which can lead to a chronic disease such as bursitis (inflammation) of the knee.
One way to counter such risks is to wear EN 340 PPE clothing.
Directive 89/686/EEC, Annex II, Art. 3.3: Protection against physical injury (abrasion, perforation, cuts, bites)
"PPE constituent materials and other components designed to protect all or part of the body against superficial injury caused by machinery, such as abrasion, perforation, cuts or bites, must be so chosen or designed and incorporated as to ensure that these PPE classes provide sufficient resistance to abrasion, perforation and gashing (see also 3.1) under the foreseeable conditions of use."
Elis offers a range in response to these two risks (Category 1 PPE), made of relatively thick, sturdy fabric. The trousers in this range may or may not be fitted with foam pads to combat the risk of bursitis of the knee.