A hazardous substance can be any substance, natural or artificial, solid, liquid or gas, that can potentially injure or harm people in and around their workplace or home.

Hazardous substances can enter the body in three ways:

• Inhalation (breathing into lungs)

• Ingestion (swallowing)

• Absorption (contact through eyes, mouth and skin)

Gases, vapours, mists, fumes and dusts are all forms of chemicals and biological agents that can be inhaled. Many of these chemicals give off poisonous fumes and can harm you if inhaled. You should always make sure that you use a respirator when handling chemicals that give off toxic fumes, dusts or gases.

Few people would ever deliberately pick up a chemical and swallow it. But have you ever sprayed your lawn or garden with a pesticide and then forgotten to wash your hands before eating, drinking or smoking? What about siphoning petrol by mouth? These are common ways in which chemicals can be ingested.

Chemicals can also get into your body by being absorbed though your skin, eyes and mouth.