A molecular model of benzene

The very first job I ever did in a laboratory, literally the first week when my lab coat was still pristine, was to try out a new QC test that had been worked up using toluene instead of  benzene as a solvent.  It had recently been decided that benzene was carcinogenic and it was no longer safe to handle.

It felt like a very serious thing to be doing and I quite enjoyed it.  It also impressed on me that some chemicals have health risks, and the carcinogenicity of benzene in particular has stuck with me as something to take seriously ever since.  I was still quite wet behind the ears then, and although I probably should have known it even then I was a bit shocked some years later to discover that benzene is found in petrol fumes (or gasolene fumes as they would say in the US).  It was quite an eye opener in fact.  We had gone to some trouble in the lab to minimise our exposure, but obviously it was a complete waste of time because there was a much bigger source that we couldn’t stop ourselves being exposed to.

It is often the case that we ignore problems if they just seem too big to deal with.  Nobody is going to stop driving their car just because of a slight health risk.  As a society we have obviously decided that mobility is worth paying the price in increased cancer incidence.  We don’t think about it much, but that is what we have done.

But what about avoidable exposure to benzene?  As I say, the lab I worked in had decided that even though we might get far more benzene elsewhere we weren’t going to have any that we could avoid. I am not sure that this approach is entirely logical, but it is understandable.  Benzene, which is a very handy solvent, doesn’t get used much in labs any more for any purpose except where only benzene will do, and then only with stringent precautions.

Benzene has never been used in cosmetics as far as I know, even before the discovery that it could cause cancer.  But there was a time when tiny traces of it would carry over from a couple of ingredients, in particular carbomer. The benzene was used in the production of the carbomer and was removed during its production, but traces of it remained.  This always used to bother me, because although the levels were really tiny you could smell it.  The logical part of my brain told me that there was nowhere near enough to do any harm and in any case I was getting the stuff all the time from driving.  But I still didn’t like it and was really pleased when the manufacturers started producing benzene free grades.  I switched as soon as practical, and so did nearly everyone else.

Funnily enough the last people to change were the pharmaceutical companies.   They were still using the old type in some formulations in the late nineties. The tight regulation of pharmaceuticals made getting a new grade approved particularly long winded.  Don’t believe anyone who tells you that regulations are always the best way to make things safer.


photo credit: jurvetson Blog – The Carbon Muse via photopin (license)

3 thoughts on “Benzene”

  1. Sorry that it’s not on topic…. The gel/cream eye liners in a pot. What thoughts do you have on what to add when they dry up? Feel free to skip my question. It came out of the blue.

    I do really enjoy your site. I wanted to read the thoughts of someone who actually knew what they were talking about. I’ve been reading here and didn’t comment for a little while. I wanted to tell you how much I enjoyed your post on lead, that Queen Elizabeth would have known it was a problem ingredient. That she was smart. That women are smart. And yes, do I take what are to me thoughtfully considered risks?

    Thank you again.

    1. I hate to disappoint but I don’t know much about those kinds of formulations. If you can point me to an ingredient list I might be able to hazard a guess on how they work chemistry wise.

      Thanks for your kind words about that lead post. You got the point exactly about women not being helpless victims.

  2. Hi Colin,

    I’ve been looking around online on topics related to Sodium Benzoate and Vitamin C as I have read that when these two ingredients are mixed it can form Benzene. I’ve been looking for a good Vitamin C serum but most of the ones I encounter contain Sodium Benzoate.

    What are your thoughts on this? Are the amounts of Vitamin C and Sodium Benzoate so small it would not react to create Benzene and if it was formed would it be harmful?

    I’ve been following your blog for a while now and you always have such informative answers! Cheers.

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