What is a substance hazardous to health

This term includes any material, mixture or compound 

Harmful biological agents, such as bacteria and other micro-organisms 

Any kind of dust with an airborne concentration of more than 10 mg/m (8-hour time-weighted average) of total inhalable dust, and more than 4 mg/m similarly of respirable dust, where no lower value is given for the substance. Respirable dust has a mean particle size that permits it to enter the deep lung, with potentially greater danger 

Any substance creating a comparable hazard, not already covered in the previous categories. Note that asbestos and lead have their own specific regulations (see below). 

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