On further research, I am not that concerned about it.  For what it is worth, I happened to notice that propylene glycol and glycerine are both ingredients in my son's Oragel Toddler Training Toothpaste.

The package says that it contains Propylene Glycol and Glycerin.  However, the package also says that it contains chemicals known to the state of California to cause cancer.  What chemicals is this warning referring to because Propylene Glycol and Glycerin aren't known cancer causing agents.

Also, my 2-year-old son may have gotten some residue of the smoke fluid in his mouth.  How much of a concern is this?