(1) The condition is called lipoid pneumonia, which comes from inhaling organic fats and oils.
(2) The CDC reports and early studies indicate that the condition has appeared in some people who only vaped with nicotine in glycerol (which is also sometimes called glycerin or glycerine).
(3) Glycerol (the Christmas molecule--HO HO HO) is a type of alcohol called a polyol, meaning that it has multiple (in this case, three) hydroxyl groups on a carbon chain.
(4) Glycerol is not a fat and cannot be responsible, on its own, for lipoid pneumonia.
(5) However, glycerol is the precursor to fat synthesis in the body: triglycerides, for example, are fats metabolized from glycerol.
(6) The reaction of glycerol -> triglycerides in the body is catalyzed by nicotine-containing enzymes mostly present in the liver, but expressed to a lesser extent in every cell.
(7) The reaction of carboxylic acid (derived from CO2) with glycerol creates fatty acid esters through the process of acid-catalyzed esterification.
(8) The key unanswered question is where does the fat that is found in the macrophages (a type of white blood cell whose function is to engulf and digest foreign substances) that is the sine qua non of lipoid pneumonia come from.
(9) Many vapers are formerly heavy smokers, meaning that they have some degree of chronic lung disease, that they retain CO2, and are very likely to have respiratory acidosis.
(10) Elevated CO2 also occurs in many other circumstances, such as opioid use and sleeping in poorly ventilated conditions.
(11) If the early reports are correct that lipoid pneumonia is occurring in vapers who have only used nicotine in glycerol with no flavoring or impurities, then we must ask the question: Is glycerol being converted to fatty acids in lung cells by NAD-mediated enzymatic conversion or acid-catalyzed esterification in the presence of high CO2 levels and acidity?