Heavy metals: Lead, mercury, and arsenic are well-known toxic metals that can cause neurological and systemic damage. Pesticides: Used to control pests, these chemicals can be harmful to humans and animals if not used properly. Pharmaceuticals: While beneficial at therapeutic doses, many drugs can be toxic when overdosed or misused. Organic solvents: Found in industrial and household products, these can cause respiratory and skin irritation. Biological toxins: Produced by living organisms, such as bacteria, plants, and animals, these can be harmful when ingested or contacted.