I'd question that. It's proving difficult to eliminate nitrosamine from supposedly pure medical grade nicotine, and this is why it's still showing up in e-liquid and NRT products albeit in minuscule amounts. If someone produces a NET and it tests negative for nitrosamine, my response is "look again".
I might be wrong here, but it's hard to see how you could produce a NET and then selectively eliminate nitrosamine, and still have it taste anything like a NET. I seem to recall seeing some tests done on NETs, and nitrosamine was indeed found but in relative small amounts compared to tobacco. I made the personal choice at that time that it wasn't the direction I wanted to go in, even though the additional risks are minor.
If they've done tests and found nitrosamine in about the same levels as that found in NRT products, then I guess you could say that qualifies as being "safe" since they think that this level of exposure is not going to significantly increase your chances of disease. This is not the same as saying that there are NO nitrosamines in the product however.
When it comes to vaping, "safe" is a relative term not an absolute one, which is why we say "safer".
I really shouldn't speak about TSNA since my knowledge is very limited. It's not an area I've researched or know much about. But as far as the testing Ahlusion does, I don't know if they've published the results or where it could be found, here's what was posted on their site; at the end of which the claim is made that their extracts tested free of TSNA..
Taken from Ahlsuion's website Summary of changes and updates.
"Services:
Our GCMS (and MSDS) analysis options will be available to the public - if you need an analysis performed and certified, we can do so. Contact us for details. This service is mainly geared towards other vendors."
Also from Ahlusion's site What's different about your flavors?.
"...Similarly, our tobaccos do not include any artificial tobacco flavor notes (Tabanon/e) as found in some Perfumers Apprentice flavorings. Yet, many are simply used to this and prefer it better. I personally hate (stress) DK-Tab, M-Type and all the rest of them and also refuse to make eliquids for anyone with those - but that's beside the point. This is also a good time to explain the two types of tobaccos we currently offer: our flavored tobaccos and what we like to call aromatic tobaccos. All our tobaccos are based on organic tobacco extracts performed in-house through various methods to achieve the desired flavors. Our flavored tobaccos simply have other natural or organic flavorings, while the aromatic tobaccos tend to resemble various pipe blends, Burleys and so on. Another important point worth mentioning, is that our extracts are tested to be free of TSNA's and other harmful products/compounds generally found in traditional tobacco or cigarettes..."