Batteries - "Fear", "paranoid", "anxiety", "There should be a battery safety quiz" (maybe the poster should go work for the Obama administration

), "fear of something that could possibly become dangerous" (Wow are you working for the FDA?

)- are all things stated in this thread and are simply way overstated.
Every day we get up and immediately face potential dangerous situations - Slipping and falling in a bath, shower, tile floor; potential electrical shook for electric devices, crossing the street, falling off a step stool, etc. -
nothing is 100% safe.
Now having a concern, learning the risk involved and how to remove most of the risk are very warranted!
Batteries have their own risk, and putting them into metal enclosures brings a whole nother level to the risk. Li-ion batteries of all kinds become relatively safe to use when following the precautions and using as designed.
Li-ion has improved and the failure rate has been reduced to
one-in-10 million according to the Battery University. But that does not remove all of the risk!!!! So learn more and respect the risk - if you fear the dangers or are parnoid of use - maybe using these things are not for you!
To bring this back to the CNA 30 -
Most places I've seen that recommend the Sony VTC4 and 5s for the clone, at the price of those batteries just get one or two and use these in the clone. Buy and use a decent intelligent battery charger for these - a Nitecore, XTAR, or EFest are common. Leaving a battery on one of these chargers while unattended leaves the safety of you and your location in the hands of those that designed and built the charger and battery - is that what you trust? If not remove the battery form the charger when you are not present and properly store it.
BTW - The Clone DNA 30 chips has quite a few safeguards built-in as well as the case being vented - all in attempt to provide a person a safer device to use. Maybe someone could restate those so my outlandinsh post does any get longer.