Final answer:
Sodium cyanide is a Division 1 very toxic substance due to its interference with cellular respiration and potential to cause severe health effects.
Step-by-step explanation:
Sodium cyanide is identified as a Division 1 very toxic substance. Cyanide compounds, including sodium cyanide, interfere with the body's ability to use oxygen, particularly in cellular respiration, which can lead to neurological effects and damage to sensitive tissues such as the thyroid gland. Cyanide is known to inhibit cytochrome c oxidase, a crucial enzyme in aerobic metabolism, leading to a form of histotoxic hypoxia. It is considered a highly toxic material and poses significant risks to human health and safety if not handled with the proper precautions and safety measures.