What might be the source of benzene in a sunscreen?

PerryPerry Administrator, Professional Chemist
Alright raw material manufacturers or people who know more about such things than me, what's your guess for the source of benzene in sunscreens?

Here's the story.  https://www.dermatologytimes.com/view/carcinogen-found-in-multiple-sunscreens  An "independent" lab looked at over 200 sunscreens an found traces of benzene in about 27%. They even named names. 

Any idea where the benzene might have gotten into the product?  Or could this just be a result of the type of testing done?

What do you think?


  • @Perry Benzene residue most likely always going to be there. I have worked with synthesis of aromatics and Freidel Crafts.Possibly the reaction for synthesis of precursor molecules is the source of benzene traces
    Benzene —>toluene—>benzaldehyde—>tertbutyl benzaldehyde(precursor in avobenzone synthesis)

    Another possible source could be fragrance components such as Lilail or benzaldehyde.Most of the organic sunscreens have fragrance

    For analytical testing, possibly using qNMR, for detection of such low levels of benzene.
  • ozgirlozgirl Member, PCF student
    Some carbomers are also manufactured using a benzene solvent.
  • PhilGeisPhilGeis Member, Professional formulator
    Think the 1st question might be the valaidity of the testing and the accuracy of report - that I'm sure the FDA is currently addressing.
  • PerryPerry Administrator, Professional Chemist
    @PhilGeis - this was my first question too. Also, if you went through and tested all personal care products, how much benzene would you find?

  • PhilGeisPhilGeis Member, Professional formulator
    edited May 2021
    Think you'd find it - at some level. 
    In addition to reproducibility, wonder at the risk assessment re. levels found.  Press release refers to 2 ppm benzene in sanitizer.  There, focus was on technical/industrial grade ethanol and FDA saw 2 ppm as acceptable for limited exposure in context of need for santiizers. https://www.fda.gov/media/136289/download

    There is the soft drink - benzoic acid/vitamin c /benzene issue..  Here they were talking about ppb levels.   https://www.fda.gov/food/chemicals/benzene

    Valisure is a new bunch - founded in 2015 - wonder how much of this is publicity., even if accurate as reported.
  • PerryPerry Administrator, Professional Chemist
    Ah yes, I forgot about the benzene in soft drinks controversy.
  • @Perry 

    Long shot here but possibly residue from cleaning hydraulic pumps and mixing shafts?   
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