Is there any good evidence that e-cigarettes are toxic or otherwise dangerous?

I’ve been hearing a whole lot of skepticism about the safety of e-cigarettes but very little hard evidence supporting what i would consider anticipatory anxiety.

What I’ve heard:

e-cigs are an ineffective replacement therapy aimed at quitting cigarette smoking
e-cigs contain the same harmful substances seen in cigarettes
there is no proof that substances inhaled in e cigarettes are any less carcinogenic than tobacco smoke
As far as I’m concerned these all sound like claims of a lack of information, cleverly worded to maybe elicit some preassumptions about the product as yet unaccounted for.
So is there any evidence that e-cigarettes are as dangerous as tobacco smoke, is it less dangerous, how much less or more dangerous is it, any long term or short term consequences??

Cigarette smoke contains somewhere around 4,000 different substances, some of which have been shown to cause cancer.

E-cigarettes contain nicotine, propylene glycol, and some flavoring, none of which have been shown to cause cancer.

The danger of e-cigs is to the bottom line of the pharmaceutical companies that manufacture nicotine patches.

While not as bad as smoking, e-cigarettes aren’t completely harmless either; nicotine itself is a vasoconstrictor and can thus cause cardiovascular problems (increased blood pressure, stroke, heart attack, etc, ulcers and possibly gum disease and oral cancer). Also, some e-cigarettes use chemicals that are known carcinogens, as stated in this FDA advisory from 2009 (though they might have reformulated since then, but then they are mostly made in China and everybody knows about their attitude towards harmful substances).

Most ecig brands also have cartridges without any nicotine at all, so the nicotine is entirely vaper’s choice.

Here you go: ‘Safe’ Electronic Cigarettes Leak Carcinogenics from electronic design. I’ll be sticking to nicotine gum then. Or cigarettes.

I respectfully submit that whatever might be in the mix, either real or imagined, is still better for the smoker than an actual cigarette. Additionally, not everything is made in China or the like. Last, until someone demonstrates that water vapor is harmful to the environment or non-smokers, I’m not terribly interested in the opinions of non-smokers regarding its health as it is just another part of the anti-smoking crusade.

Most of the illnesses associated with tobacco use take many years to develop. E-cigs have only been available for a few years. There haven’t been many valid studies done yet, and as noted upthread, most interested parties have a financial stake in either traditional tobacco products or e-cigs.

Hereis one of the few available scientific studies I can find that was performed by researchers with no financial stake in either tobacco or e-cigs that has been published in a respected scientific journal. The report reviewed 16 laboratory studies that identified the components in electronic cigarette liquid and vapor. The authors found that carcinogen levels in electronic cigarettes are up to 1,000 times lower than in tobacco cigarettes.

Notice that the link from Fridgemagnet is an article by a staff writer in an electronics magazine, not a scientific study.

The study mentioned in that article is not really my idea of an unbiased scientific study.:

And it still makes no specific claims, only vague scare words.

Also from that article:

Those manufacturers “managed to win” because the FDA claims were bogus. The claims of toxic chemicals in the e-cigarettes weren’t made by the FDA but by organizations with an agenda.

I am quite certain of my statements because in the article linked to by Michael63129

one of those 50 shipments seized by customs was mine.

I’ve searched the web fairly thoroughly - out of personal curiosity. The real truth is that the jury is still out. I could find no study showing any harm - either increased harm vs. tobacco cigarettes or FDA approved replacement therapy (gum/patch). Most evidence shows significant harm reduction, but that evidence is not accepted yet as fact.

I did find a New Zealand study that concluded ecigs are totally harmless - save for any known nicotine side effects, including second hand exposure.

There is no complete (long term) US study available. But, initial studies are promising. And while SOME samples of China produced ecig liquid included carcinogens, no US manufacturers were tested.

US manufacturers generally list their ingredients on their websites (though I don’t believe there is a requirement to do so). Their ingredients are all individually FDA approved, pharmaceutical/food grade components.

Producers of both the devices and the liquid used in them are neither pharmaceutical companies or cigarette companies (though I read very recently that a tobacco company did buy out an ecig company). Both pharma and tobacco have a vested interest in seeing ecigs fail.