Prof Dame Sally Davies, England's chief medical officer, said:
"E-cigarettes can produce toxic chemicals"
What toxic chemicals exactly?
Well "toxic" is one of those 'doesn't really mean what you think it means' weasel words.
Technically. All of them. Every chemical produced by an e-cig could be toxic.
Toxic is more a function of dose. Everything could poison you, provided that you ingest enough of it, including such evil nasty things as water and oxygen.
If you're talking to the average person then the phrase "can produce toxic chemicals" means more, 'might produce enough of a dose of a chemical to harm my health'. In which case the answer is none of them.
Back in 2009 a study by the FDA found contaminants in some of the early e-cigs on the market. Specifically di-ethylene glycol. Which is one of the chemicals in anti-freeze and IS a toxic chemical by both definitions.
This study was flawed and it badly misrepresented it's results. It tested 18 cartridges and found di-ethylene glycol in ONE of the cartridges tested at a level below 1%. Further independent tests didn't find any. No subsequent tests have found any, and in fact companies like ECITA now regularly test members e-liquids/carts for the presence of di-ethylene glycol using a GC-MS scan and to date have found ZERO (and presumably by this point have run thousands of tests)
Also in 2009 the same study found traces of Tobacco Specific Nitrosamines. Basically these are chemicals related to nicotine that it is impossible to remove completely. (USP BP Nicotine is 99% pure and that other 1% has got these chemicals in it) All NRT products that use Pharma grade nicotine contain these chemicals
at the same levels as those found in e-liquid and a smoked tobacco cigarette has levels of these chemicals
1200 times higher.
NRT products have medical authorisations and they contain the same levels of these "toxic chemicals", in other words that level has already been deemed a safe one. So arguing this as the basis for toxic chemicals is more than a little disingenuous.
There is also the old fallback "nicotine is a toxic chemical" and yes, more than any other of the chemicals released by an e-cig this is technically true. However used as intended the dose of nicotine delivered is essentially harmless. Potentially a young child using a very high strength e-cig (higher than 36mg) MIGHT have an problem, but it's hard to say, and under 18s should not be using them anyway.
Basically it boils down to: If you are using the man in the street definition then they are lying. There are no toxic chemicals in e-cigs, and the 2009 study which found some small amounts of some has long since been discredited by multiple, more recent studies, of which the public health people by now should be more than well aware.
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link to CASAA article that goes into more detail (pdf)]