Horrible study. There was not so much as a linear regression and the statistics were horrid (not to mention the complete absence of mathematical calculations, a table containing the origin of the calculations, etc). Comparison to diesel fuel ... where's the math, let me see it .. where's the chemistry .. why are they similar? This study is nominal at best. It was a hypothesis without much info to back it up. If they had a control group of people who didn't burn candles compared to another group that did, and used health as the independent variable, I would be more apt to believe that the health hazards were real.