I’ve read this article in detail. The findings actually show that PG and PEG are pretty safe. Those levels of the chemicals of concern are very low. There are higher levels found naturally in our bodies because of our metabolism and in fruits and coffee. One inhalation = 1% of the daily exposure limit? If you gotta hit the pen 100 times a day that probably means your cartridge is weak sauce.
Also, they are heating PURE diluent (PG/PEG/VG/MCT) so you would have to correct somewhat for the absolute quantities. Cannabis vape products wouldn’t likely contain more than 10% diluent at most (one would hope). So does that mean each hit is about 0.1% of the daily limit? I dunno.
In any case, I am really concerned about the potential health effects of inhaling MCT regularly. All the arguments supporting its safety are purely hypothetical at this point. Only time will tell if it is safer than vaping coconut oil. Also, you have NO idea about how pure MCT oil is or any potential contaminants (heavy metals, long chain triglycerides, etc etc) when you buy it. I would imagine it would be harder to find a pharmaceutical grade MCT oil than it is to find pharma grade PG or PEG. Just my two cents.