'non-hazardous' originates from the prefix 'non-' meaning 'not' and the word 'hazardous' which comes from the Old French 'hasardeux', meaning 'dangerous'.

'hazardous' changed from the Old French word 'hasardeux' and eventually became the modern English word 'hazardous'.

Initially, 'hazardous' meant 'dangerous or risky', and 'non-hazardous' evolved to mean 'not dangerous or risky'.