A substance hazardous to health is a substance or preparation (mixture) with the potential to cause harm if they are inhaled, ingested, or come into contact, or are absorbed through the skin
The COSHH Regulations apply to any substance:
a) which is listed in Table 3.2 of part 3 Annex VI of the CLP Regulation and for which an indication of danger specified for the substance is very toxic, toxic, harmful, corrosive or irritant;
b) for which the Health and Safety Executive has approved a Workplace Exposure Limit
c) Which is a biological agent
d) Which is dust of any kind, except dust which is a substance within paragraph (a) or (b) above, when present at a concentration in air equal to or greater than
10 mg/m3 as a time weighted average over an 8 hour period of inhalable dust or
4mg/m3 as a time weighted average over an 8 hour period of respirable dust
e) Which, not being a substance falling within sub-paragraphs (a) to (d), because of its chemical or toxicological properties and the way it is used or is present at the workplace creates a risk to health