I have read in many places online that neoprene coated dumbbells may cause cancer. Just how carcinogenic are they? Would normal use of said dumbbells (say less than one hour per day) be of any risk?


I just bought a 32 lb neoprene dumbbell set and took it out the package and noticed a warning on the bottom: "This product contains one or more chemicals known to the state of California to cause cancer, birth defects and other reproductive harm."

  • I haven't found any answer so far. – Franck Dernoncourt Jul 24 '16 at 16:10
  • So I am still interested if someone has any idea. – Franck Dernoncourt Jul 24 '16 at 16:10
  • Well, they don't smell very good. Obviously beside the point though! I would be interested in seeing an answer as well because I'm wondering if it's actually the coating or if it's what gives it it's weight. – L.B. Feb 2 '17 at 15:09
  • Possible duplicate of Safety of using a luggage with the prop. 65 warning – Mark Feb 8 '17 at 1:48

The chemical name for neoprene is polychloroprene and is a polymer of chloroprene. Chloroprene is suspected of causing cancer, but that does not mean that its polymer causes cancer. For instance, ethylene is a gas used to ripen, among other things, bananas, but its polymer--poylyethylene--is the basis of many plastics; ethylene and polyethylene are nothing alike, just like chloroprene and polychloroprene.

If some substance does not cause cancer, it's highly unlikely that you will find literature that expressly states that.

That example you cite is most likely referring to the chloroprene in neoprene. However, that chloroprene is tightly locked up inside its polymer. It would take a strong chemical (stronger that your sweat) to unbind the chloroprene in neoprene.

  • The study you found is about chloroprene, not polychloroprene. There's a big difference in potential carcinogenity: the long-chain molecules of the poly form make it much less reactive. As an analogy, inhaling powdered sandstone will give you silicosis; trying to inhale a sandstone boulder will just make you look silly. – Mark Feb 8 '17 at 1:52
  • @Mark, you are absolutely correct. How I made such a stupid mistake is beyond me, as I do know the difference between a chemical and its polymers; they are nothing alike. I have edited my answer accordingly. My apologies to anyone who may have read this. – BillDOe Feb 16 '17 at 0:09

Looking at Wikipedia, there is a chemical that is used to accelerate the vulcanization process in neoprene called Ethylene Thiourea (ETU). This chemical is reprotoxic (causes reproductive harm), but its depends on the concentration. I would imagine there are still traces of the chemical left on the material after the manufacturing process, so they need to list it.

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    We expect more here than "looking at Wikipedia." Please provide a reference to a credible source. – Carey Gregory Jul 25 '17 at 2:00

Neoprene is used by sailing professionals in a piece of clothing called a wetsuit. They wear this for periods of many hours in length. This should speak to the effect of the material and how safe it is.

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    Welcome to Health.SE. Since health is an important topic, the site has a strict policy that all answers should be backed up with reliable references in order to provide the community with the means to assess the merit of the answer, regardless of the reader's background. See this list of reliable sources. If you still have trouble with this, feel free to visit the help center. – Narusan Apr 19 '17 at 3:59
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    Asbestos was used for many hundreds of years as fireproof material. That's a good testament to its effectiveness, but doesn't make it any safer. – Mark Jul 25 '17 at 20:55

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