Australia Model Code of Practice: Managing Risks of Hazardous Chemicals in the Workplace 3.3a: 3.3 Assess health risk from the route of entry, form, concentration and properties of the chemical

Health risk depends on hazard severity and level of exposure and on the work itself, and the assessment must consider all workers potentially at risk and visitors. Use the hazard classifications and routes of exposure (inhalation, ingestion, skin or eye contact) from hazard identification: for crystalline silica the concern is inhaled respirable dust and long-term lung disease, while for sodium hydroxide immediate skin, eye and respiratory effects mean all routes need review. Some chemicals have ototoxic effects and should be assessed alongside noise controls. Physical form matters (a solid block versus fine dust, fumes or splashing solution) as does concentration, and gases and liquids of low boiling point or high vapour pressure give high airborne concentrations while oils need heat or spraying. Odour must not be relied on to detect a hazardous chemical, because for example not everyone can smell hydrogen cyanide and high levels can overload the sense of smell.