Since gasoline can burn and its vapors can explode, gasoline is also hazardous. A chemical can be toxic, or hazardous, or both. Since chemicals can be toxic, it is important to understand how they can affect health. Some substances are more toxic than others. The toxicity of a substance is described by the types of effects it causes and its potency.
Different chemicals cause different effects.
For example, Chemical A may cause vomiting, but not cancer. Chemical B may have no noticeable effects during exposure, but may cause cancer years later. A more potent chemical is more toxic. The potency and, therefore, the toxicity of a chemical can be affected by its breakdown within the human body. When a substance is absorbed into the body, its chemical structure may be changed or metabolized to a substance that is more toxic or less toxic.