I would not delve into any of the concentration camp topics! When did I give you the idea that I am conversationally suicidal? ;o)
I would refer you to Mr. Google. There's enough material there to give you food for thought for some months. (Pat didn't just pick these questions up out of thin air, for heaven's sake).
Speaking of Google ... I found this article made some interesting points:
http://home.ddc.net/ygg/rj/rj-03.htm
Here is one of the most comprehensive commentaries on Buchanan's diesel fumes remarks.
http://www.holocaust-history.org/~jamie/buchanan/
Basically, there is not much merit to his claims that people cannot die from the inhalation of diesel fumes. (If nothing else, they will die from lack of oxygen.)
But what is more enlightening is that Buchanan's views are the same ones made by Holocaust deniers.