What Twisted Victor said was what I always believed before I had my pants scared off of me by this entire thread. It has been my understanding (and what my doc told me) that you will start to feel sick long before any actual mortal harm would take place. I believe his words were something to the effect of "having to be very determined to od on nicotine from smoking, snus, and vaping" all 3 of which I was using at the time. Someone please correct me, I'm sure they will

, if I'm wrong.
This is correct. Another issue that did not seem to come up in this thread, probably because it was started long before the tests were made, is that even if you are vaping 3 mL of 36 mg nic juice a day, you are still taking in about 1/10 the amount of nic as smoking a pack of full-strength analogs. This was tested clinically, and posted elsewhere here (can't remember where just now, but it WAS measured). These are blood tests on nicotine and its common metabolites. Fact: the ecig is not a very efficient nic delivery system.
However, there IS a risk of topical nicotine toxicity with high-nic juices. Get a squirt into your mouth of high-nic juice and you will feel it! It burns like pepper, gives you hic-ups (I call them nic-ups) and parts of your mouth after a minute or so can go numb. You may feel queezy. It still isn't lethally dangerous, just wash your mouth out with water.
Yes, PURE nicotine on your skin can make you very sick or kill you. But you are not dealing at all with pure pharm-grade nic, unless you are a juice producer, where there is a real danger. OTOH, spill a whole bottle of 36 mg juice on your inner thigh or underside of forearm (both thinner skin) and you could be in serious trouble.
Of course, get inspired at a wild party to do shots of an entire bottle of vodka and guess what, you are probably dead. Even half a bottle binged all at once will likely put you into the ER.
Patches will make you very sick or kill you from heart attack if you forget you have it on and smoke analogs, and they are OTC! I've known two people that this happened to, and I don't even know many that use the patch. How f-ed up is that?? have an analog during a vape break and you will not likely even get sick. And chances are you will not even smoke the analog anyway when vaping.
The Patch to me is the gov't/BP saying ok nasty smoker, you want nicotine, HERE'S YOUR FRIGGING NICOTINE!! HAVE FUN, ......!!! The patch is also a seriously flawed delivery device. It gives you lots of nicotine all the time, does not stop, wake or sleep, you are going to be on the ceiling with nicotine. Absolutely zero like the rhythm of smoking, and who wakes up every 10 minutes at night to have a smoke??
Yet another example of an approved system designed and distributed by non-smokers that have no clue at all.
Another thing I wanted to mention is that two smokers both smoking a pack of Mar Reds a day may have differnt smoking habits and ingest different amounts of nic. One may inhale deep and hold the breath before exhaling, the other may inhale shallow and exhale right away. The nic is largely adhered to the smoke particles, so this is going to make a big difference in serum nic levels. The majority of nic when vaped is absorbed into the mouth and throat, not the lungs, so these two methods in terms of vaping would probably result in more similar serum nic levels, both of which will be far less than from analogs, anyway.
my $0.02.