There still seems to be a lot of confusion about the antifreeze issue. When the FDA stated that they found "an ingredient used in antifreeze" in one of the samples of e-cigarettes they tested, they were not talking about the Propylene Glycol (PG). The FDA specified that they found 1% Diethylene Glycol (DEG) in one of the samples tested.
DEG is much more toxic than PG.
The first rule of toxicology is that "The dose makes the poison." What this means is that almost anything is toxic in large enough quantities, and almost anything is safe is small enough quantities. Talking in percents doesn't give enough information to determine whether the quantity of DEG is actually dangerous. But if you figure that the Smoking Everywhere cartridges hold, at most, 0.5 ml of liquid, then 1% of that is 0.005 ml (grams) of DEG.
The median lethal dose (LD50) of DEG for humans is approximately 1 gram per kg of body weight. A very light weight adult might weigh about 50 kg, so they would need to ingest 50 grams of DEG to reach the LD50. At 0.005 grams of DEG per SE cartridge (assuming all cartridges contained that much DEG, which is doubtful since the FDA only found one), our 50 kg adult (about 110 pounds) would need to ingest the contents of 10,000 cartridges to reach the LD50 of DEG--in a single day, since DEG clears the body within 24 hours.
If the liquid also contains nicotine, our 50 kg adult would reach the LD50 of nicotine (oral) much sooner than the LD50 of DEG.
But wait! E-cigarette users don't drink the liquid--they vaporize it.
How much DEG did the FDA find in vapor? None.
See:
FDA's partial truths and exaggerations endanger health