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Prop 65 and cocamide diethanolamine

Dear Reader,

It has come to my attention that a court case which relates to fatty acid N,N-dihydroxyethyl amides, it relates to what I think is a stupid law in California. The reason why I think that Prop 65 is stupid is that the law paints so many chemicals and substances with the dire warning of “WARNING: This product contains chemicals known to the State of California to cause cancer and birth defects or other reproductive harm.

The problem is that california has the potential to be “swamped in a sea generic warning signs” these are the words of the Attorney General in california. See page 25 of this document. The great problem is that so many things can cause birth defects and other reproductive harm but are exceptionally weak agents of harm.

For example aspirin (salicylic acid), beer and cigarette smoke have teratogenic effects. Alcohol is a weak carcinogen in humans. But is it reasonable to plaster a crate of beer with the same generic warning as you put on a real nasty substance like HMPA, asbestos, beryllium oxide, methoxyethanol or DES (Diethylstilbestrol). I am strongly in favour of putting a clear warning on a substance or area which has a strong carcinogen or teratogen, but I am very much against misusing warning signs by fly posting every surface with a bland warning.

The latest court case which I have heard about involves cocamide diethanolamine, I think that while some evidence exists to suggest it can cause cancer in animals it is interesting to know that no evidence for carcinogenic action in humans exists. But the best bit is that it does not flunk the Ames test. For a copy of the IARC report on this compound see here.

Many carcinogens fail the Ames test which is based on Salmonella typhimurium, While some false positives and false negatives occur with the Ames test it is a good test for spotting substances which damage DNA. To cause cancer from healthy normal cells some DNA damage is needed, but it is interesting to note that some carcinogens are substances which promote cancer. They speed up the growth of cancers, for example many steroidal sex hormones can speed up the growth of cancer and as a result some of them carry the R45 warning when you look them up at Aldrich. For example testosterone (CAS [58-22-0]) has the R45 warning.

I have looked up at Aldrich the closely related compound lauric acid diethanolamide (R36/38 which means irritant), and this substance is not flagged with a carcinogen warning. For good measure I looked up the amine which these amides are made from (diethanolamine, CAS [ 111-42-2]) and yet again there is no cancer warning in the risk phrases which are associated with this compound, but it does mention genetic damage.

So I dug into the chemical literature, and I found something interesting. A review of the carcinogenic activity of diethanolamine (DEA) in rodents was written by Hon-Wing Leung, Lisa M. Kamendulis and William T. Stott (Regulatory Toxicology and Pharmacology, 2005, 43(3), pages 260-271). I have looked at this paper and it does state that dermal exposure to diethanolamine causes liver cancer in mice. By the way dermal exposure means putting it on the skin.

While in mice DEA (Diethanol amine not “drug enforcement agency“) and related compounds can be shown clearly to cause cancer, in rats these compounds these compounds do not appear to be carcinogenic. Hon-Wing Leung’s paper suggests that the DEA exerts a carcinogenic effect by altering the behaviour of a key nutrient for rodents (Choline) in the experimental animals. This alteration in the choline behaviour alters the biological methylation in the mice which may lead to cancer.

The final big point from this paper is the comment that Hon-Wing Leung et. al. made that humans are far less sensitive to choline deficiency than rodents, so the observation of the carcinogenic action of DEA in mice may not be relevent to humans. So I think that the court case which relates to using Prop 65 on personal care products is a bad court case.

I think that while prop 65 was passed with the best of intentions it has turned into a monster (and a silly one at that), what I think should be done is the law should be altered. The warning should only be used when a reasonable chance exists that a product, process or place will result in a person being exposed at a level which has a “reasonable” chance of causing harm. When the level is below this limit then no sign should be used, also the public should have the right to make reasonable requests for the concentrations of substances.

Where the concentrations of the substances are less than 10 % of my limits then I think that if a NGO makes a request for the concentration measurement then the NGO should have to pay for the measurement. Also vexatious requests from the general public should be treated in the following way, if the testing suggests that the concentration is below 10 % of the limit then the member of the public should be billed if they have made more than n requests in the last five years where the result has been less than 10 % of the limit. I will leave it up to the courts and the government to choose what value n should be.

Maybe for each test requested by “John Doe” which shows more than the limit he should get x free tests extra. This would make people choose the tests they want with some care rather than demanding the whole city is tested for everything with one sample being taken each meter on a grid which covers the whole of LA !

On the other hand for some places and types of activity should be required to pay for some testing to make sure that they stay within the legal limit. For example an indoor car park (parking lot for my US readers) should be required to make sure that carbon monoxide levels are kept low by using passive CO detectors which can be left in place for weeks on end.

The limit could be chosen for a substance which acts in a random (Stochastic) way, if we assume that the radiation dose to cancer risk is 5% for each Sv of dose. Then we could use the 1 mSv annual limit for the general public as the start point for our reasoning, this would mean that if a person is exposed to more than 1 in 20000 chance of harm to them, or a 1 in 100000 chance of having a child with a birth defect then the law should apply.

While for a person using a single product which could harm them this is a good limit, for a person who is exposed to several products we need a more complex system. I think that an hourly risk equivalent to 2.5 microSv (a 1 in 400000 risk per hour of death) is too high. You might want to consider a person such as a bar man who is exposed to second hand smoke.

I would set the risk per hour more strictly than the UK workplace radiation law (Upper limit for an area which the general public can enter, 2.5 microSv per hour the last time I looked at IRR99), this could be viewed as being based on a 40 hour working week. If we set it based on a 100 hour working week then we would get a 1 in 1 million risk as the hourly limit for death of a person while we would then end up with a 1 in 5 million for the birth defect risk. Maybe I am being too strict or maybe I am being too relaxed, again I would leave it up to the law makers to choose what “working week” to base their reasoning on.

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2 Responses

  1. The following information is from MDS on cocamide diethanolamine:

    Hazardous in case of skin contact (irritant), of eye contact (irritant). Slightly hazardous in case of skin contact
    (permeator), of ingestion, of inhalation.
    CARCINOGENIC EFFECTS: Classified 2B (Possible for human.) by IARC.
    MUTAGENIC EFFECTS: Not available.
    TERATOGENIC EFFECTS: Not available.
    DEVELOPMENTAL TOXICITY: Not available.
    Repeated or prolonged exposure is not known to aggravate medical condition.

    • Group 2B of the IARC classification means

      “Group 2B: The agent is possibly carcinogenic to humans.

      This category is used for agents for which there is limited evidence of carcinogenicity in humans and less than sufficient evidence of carcinogenicity in experimental animals. It may also be used when there is inadequate evidence of carcinogenicity in humans but there is sufficient evidence of carcinogenicity in experimental animals. In some instances, an agent for which there is inadequate evidence of carcinogenicity in humans and less than sufficient evidence of carcinogenicity in experimental animals together with supporting evidence from mechanistic and other relevant data may be placed in this group. An agent may be classified in this category solely on the basis of strong evidence from mechanistic and other relevant data.”

      This means it might be a carcinogen in humans, but this is only a may be.

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