where can the worlds deadlist chemical be and why is it so harmfull

Question: where can the worlds deadlist chemical be and why is it so harmfull
- Keywords:
  chemical,
  deadly,
  harmful
Asked by OMGMaster2005 to Huma, Jack, Lucy, Miranda, Peter on 16 Nov 2016. This question was also asked by kaiblazz'n (cameron).
- Peter Boorman answered on 16 Nov 2016:
  
  Hi OMGMaster2005,
  
  One of the most dangerous naturally occurring chemicals is probably Carbon Monoxide. This chemical is so dangerous because it is highly poisonous to living animals, but is also odourless, so is difficult to detect in air.
  
  Peter

Question: where can the worlds deadlist chemical be and why is it so harmfull