4. Hydrogen cyanide (HCN)
The chemical agent or hazardous material that interferes with the body’s ability to transfer oxygen to the cells is Hydrogen cyanide.
More information:
Hydrogen cyanide is a colorless or pale-blue liquid or gas with a bitter, almond-like odor.
It can interferes with the body’s ability to transfer oxygen to the cells and may cause harm to body's part like brain, heart, blood vessels, and lungs... etc.