The term "harmful substances" refers to any chemical or physical agent that can cause harm, injury or discomfort when it comes into contact with a person's skin, eyes, respiratory system or other organs. These substances may be in the form of gases, liquids, solids or even radiation and they have varying degrees of toxicity depending on their concentration, duration of exposure, and the sensitivity of the individual exposed. Examples of harmful substances include chemicals such as acids, bases, poisons, allergens, irritants, carcinogens, teratogens, mutagens, and other toxic materials that can cause adverse health effects ranging from mild skin irritation or respiratory problems to severe poisoning, burns, cancer or even death. It is essential for individuals to take precautions when handling these substances, follow safety guidelines, wear protective gear and be aware of the potential hazards associated with them in order to minimize their risk of exposure and prevent harm.