toxicity of phenol

[noty]

Hi, can anyone tell me how much toxic a phenol solution is. For eg. is a solution of 100 mg/L dangerous, if prepared in lab without hood??

Till what limit can we prepare a phenol solution without vent hood??

[YT2095]

take a look here: http://physchem.ox.ac.uk/MSDS/PH/phenol.html

 

in particular read the LD50.

[woelen]

I'm not that concerned by low LD50's (it is not that low, btw, if that value of 140 mg is correct, then for a grown up person you would need 10 gram or so, which you definitely will not swallow).

 

The real concern is its long term effect. Phenol is a very harmful compound, especially in the long run. When you work with it on a day by day basis and you smell it every day, then you really need to worry. If you work with it only once, then I would be careful (e.g. try to avoid breathing vapor, do not get it on your skin, etc.) but when you use common sense in that case I would not worry too much. So, it all depends on how frequently/how long you will use it.

 

I myself have no real fear of working with very toxic chemicals (even NaCN does not really bother me), as long as there is no long-term effect and as long as it is incidental. Direct poisoning and being killed is an extreme rare thing and only happens to stupid people who do not know what they are doing. Always perform a risk assessment before working with dangerous chems. E.g. think about what you would do, in case your flask breaks and 10 grams of highly toxic stuff flows out. Think about that beforehand and not at the moment when it surprises you.

[noty]

Thanks woelen for your nice suggestions, actually i just need to work on it 5-6 time a month, and i hope it will not be a matter of problem. I will just make a stock solution once in a month. Actually somebody told me that it is too dangerous, i searched on net but could not find anything about it when it is in solution form (< 2g/L).

 

But still i have queries, actually i want to know, If i work once in a week on 100 mg/L phenol at a place without hood, will it be a problem to me or anyother persons in the lab. Actually i havent read anything about it.

 

Secondly at what concentration level do you think it is good to be more careful or do you suggest when i will handle pure phenol ony then .

[woelen]

I would say, if you can smell the stuff, every time when you work with it, and you do that 5 to 6 times per month, then to my opinion that is too often and you should either try to find an alternative, or take measures that you are not exposed to it.

 

Of course, if this work with the chem is just for a few minutes (e.g. pouring some of the solution over into something else and that's it), then I would not worry, but if this 5 to 6 times per month means working many hours with the stuff, then I would worry.

[John Cuthber]

IIRC the carbolic acid that Lister used in the pioneering days of antisepsis was 1% phenol ie about 100 times more concentrated than the solution you are using. Since his patients (and the doctors) survived spraying it around, I think it's fair to say that you don't need to worry too much.

Of course, as with all toxic chemicals, it's prudent to keep exposure low.

[woelen]

No, this solution is not 100 times more concentrated, only about 5 times concentrated. But again, repeated exposure I would really try to avoid. A one-shot exposure is not that terrible.

[John Cuthber]

OK, It's been a while so I apologise for bumping this but... If this quote about Lister

"He also made surgeons wear clean gloves and wash their hands before and after operations with 5% carbolic acid solutions. Although it should be noted that he first persuaded Robert Goodyear to manufacture rubber gloves for his nurse since the carbolic acid caused her to suffer from contact dermatitis. Instruments were also washed in the same solution and assistants sprayed the solution in the operating theatre. One of his conclusions was to stop using natural porous materials in manufacturing the handles of medical instruments."

from wiki is right then Lister was using 5% phenol, that's 50g/litre. Last time I checked 50,000mg/L was not 5 times as concentrated as 100 mg/L. I apologise for underestimating the difference- the stuff Noty was talking about is 500 times more dilute.