This episode is the 2nd part of interview with Professor David Purser, this year recipient of IAFSS'14 Emmons Plenary Lecture. If you have not seen it, I would highly encourage you to first listen to the Part 1, which sets the context of the discussion here.In Part 1 we have talked a lot about the toxic hazards and how the production of toxicants has evolved together with fire loads. We have also gone quite deep into the toxicity of CO. In part 2, we cover the combined effects of asphyxiant gases and some of the HCN toxicity. We also distinguish between asphyxiants and irritants, discussing in depth how each of those work on the human body, and what are the physiological and pathological consequences of exposure. We also go quite deep into how tests on animals were carried, in consequence - what we know about the effects of these toxicants on the human body (and what we just assume...). We finish the episode with quite an engineering take on building useful models and progressing the toxicology further.These two episodes. Seriously, maybe it is just me, but I feel this is some sort of pinnacle of how informative an informal chat in a podcast may be. I have just learnt more about toxicology than in 13 years of my professional career and in my formal education (maybe it was just bad, dunno...). Please apologize me if I am over-hyping this, but I am absolutely thankful to David for spending some of his time with me and teaching me all of this. I hope this will be useful for generations of fire engineers!