140
"The scientists analyzed the metal and metalloids inside seven types of disposable devices from three of the most popular brands. Using an instrument to activate the disposable e-cigarettes and heat the internal liquid, they created between 500 and 1,500 puffs for each device. They found:
Some devices emitted surprisingly high concentrations of elements in the vapor, including antimony and lead. Levels of chromium, nickel and antimony increased as the number of puffs increased. Most of the disposable e-cigarettes tested released markedly higher amounts of metals and metalloids into vapors than earlier, refillable vapes."
https://www.ucdavis.edu/news/disposable-e-cigarettes-more-toxic-traditional-cigarettes
Ah, but here's the twist, most of them are already officially "illegal" but are still sold mail order and in corner stores none the less. It is an enforcement problem, not a regulation one.
Also of note, the big tobacco manufactured brands like NJOY and BLU actually have pretty substantial testing done on them. I met one of the analytical chemists who does the testing. What is there tolerance level for metals? I dont know, but probably better than the Chinese import all-in-ones. Based on this data though, seems like D Pods are the best pick all around if you have to pick one, so big brand D Pods are probably best overall, but then they dont have the flavors the kids all clamor over due to actually following regulation.