Some substances are more toxic than others. The toxicity of a substance is described by the types of effects it causes and its potency. 1  Types of Effects: Different chemicals cause different effects.
I think I remember reading that injured means bruises and lascerations, seriously injured meant hospital but not life threatening, critically injured meant hospital ICU time and fatally injured meant injuries leading to dying sometime later.
Legal Definition of great bodily injury. : physical injury suffered by the victim of a violent crime that causes a substantial risk of death, extended loss or impairment of a body part or function, or permanent disfigurement : physical injury that is more serious than that ordinarily suffered in a battery.