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.
Critical means severely ill , not out of the danger zone , stable means no further deterioration e.g. no new problems with circulation , ventilation / oxygenation ( breathing or mechanical ventilation ) , kidney function , liver function , bowel function , blood clotting and brain function as far as can be gauged in these very sick patients often ...