M-Class dust is considered medium risk. While this type may not pose the same long-term health risks of class H, it is still highly recommended that you protect against it. Dust class M is common in most industrial workspaces with wood and quartz-based materials the most common cause. Other M-class dusts include MDF, some stone, cement (standard or tile), concrete, mortar, repair compound and paint (oil and latex).

M class extractors come fitted with a flow sensor and alarm that advises the user when a dust bag or system is full, or if attention is required. As this dust class is considered more hazardous, it is vital that hardware is kept running at an optimal level at all times. M  class extractors and filters operate at 99.9% efficiency. That means there is an occupational exposure limit of 0.1mg/m3.