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Ethidium Bromide Agarose Gel Hazard - (Sep/21/2012 )

Hi folks,

I have the unenviable task of demonstrating to a large group of final year undergrads how to run DNA gels.

We use a 0.5ug/ml EtBr containing Agarose gel for the electrophoresis. After my gel had set I was setting the rig up when a tiny bit of the gel managed to flick onto my skin (the tiniest sliver of bare skin between my sleeve cuff and my glove....typical). It really was a very small amount, and the gel was more or less set by that stage. I gave the whole area a good scrub with soapy water several times.

Anything to be worried about do you think? I'm quite paranoid about these things as my PhD was looking at chemical carcinogenesis!

Any advice would be welcome!

All the best,



I think we'd all be dead if there were anything to worry about.


phage434 on Fri Sep 21 13:00:31 2012 said:

I think we'd all be dead if there were anything to worry about.

Great, I was thinking it wouldn't be as bad as people make out. Cheers.


Yeah - EtBr was (possibly still is) used as a prophylactic and treatment for sleeping sickness in cattle at about 1 mg/kg (that's milligrams/kilogram - just so you don't think its a typo) with no observable effects.


And another thing: unless you are cut on that skin portion and you have an open wound in which you pour the toxic stuff, you do not get intoxicated by most of the things in the lab as long as you wash the affected area immediately. My rule of thumb for anything in the lab labeled as toxic :P We'll see in 30-40 years (when and if I get cancers) if it was valid. But as phage said: we would all be dead by now if all of these stuff would be as toxic as they claim. Besides what bob said about EtBr, think only about chloroform: highly carcinogenic now; they were using it as anesthetic ca 50 years ago.


Thanks for the responses guys. Yeah, I was kind of thinking that there was a bit of unnecessary hype surrounding it. That is a pretty interesting point bob1, I had never heard about that.


Good advice here but as a reminder - don't go mad. EtBr is potentially dangerous and is a potential mutagen. I'm not saying that you should be worried but take the precautions that you should (PPE, et cetera) and treat the stuff with respect. A small dose is likely to cause no problems, but, as you'll know there isn't a predictable relationship between small doses of most mutagens/carcinogens and the long term health risk.
I shouldn't imagine that skin is particularly permeable to EtBr, so if you get some on you then get it washed off immediately with copious amounts of water and then carry on.
So, as long as you take the suitable precautions and behave sensibly you'll be fine.

Fun fact: During the Victorian period people used to spike alcoholic drinks with chloroform. I think that it exacerbated the effects of the alcohol.
And the cautionary tale...all those Victorians are dead now.