Chemicals and Breast Cancer
What is the Connection and What Can I Do?


BHP: Would you explain, in layman’s terms, how clear is the evidence that breast cancer can be linked to environmental causes?

NANCY EVANS: The evidence is quite clear in terms of certain chemicals increasing the risk of breast cancer.  For example, chemicals such as estrogens and compounds that act like estrogen.  But we live in a kind of chemical stew and there are 100,000 plus chemicals in use today according to the National Cancer Institute. 

    And so we’re exposed to multiple chemicals every day at home, at work and everywhere in between.  Only a fraction of these chemicals have been tested for their effects on human health.


   I think we also need to keep in mind that many of the chemicals of concern in relation to breast cancer are also linked with other cancers and other diseases such as endometriosis, Parkinson’s disease, learning disabilities and a host of other diseases and disorders.

    There’s really an epidemic of chronic disease in this country and a growing body of science suggests that environmental contaminants are contributing to this epidemic.  You can find out more about health and environment on the web site for CHE.  CHE stands for the Collaborative for Health in the Environment and that site is


BHP:   I think I remember hearing through the CHE site that it’s not just estrogen that these chemicals disrupt. It’s the thyroid function and even insulin can be disrupted by these very same chemicals that are linked to breast cancer.

Nancy Evans:    That’s absolutely right.  The CHE site has a really excellent database that you can search by disease or by chemical so if you look at benzene for example, you’ll find a list of diseases associated with exposure to this carcinogen or you can look at breast cancer and get a list of chemicals associated with increasing the risk of the disease.

    And one of the nice things about this site is that the evidence is listed in three categories.  Strong evidence.  Good evidence.  And limited evidence.  And for a number of chemicals there is only limited evidence about links to disease and that’s because they haven’t been studied.  Not because there wouldn’t be evidence there if they were studied. 

    So the Breast Cancer Fund is a founding partner in CHE and much of our work is collaborative with other organizations who are also partners. 

    But before we move on, I’d like to make one other important point.  And that is that none of the evidence linking chemicals and breast cancer is as conclusive as the evidence linking ionizing radiation and breast cancer.  Ionizing radiation is the kind of radiation you’re exposed to in X-rays and CT scans, fluoroscopy and other medical procedures –



Nancy Evans: Mammograms.  And in 2005 the National Toxicology Program added X-radiation to the list of known human carcinogens.  Which is why we desperately need an alternative to mammograms because it makes no sense to expose women to a known carcinogen in order to detect cancer.  There’s just something totally illogical about that.


BHP:  We interviewed someone about thermography but he was very clear that thermography will not and cannot replace mammography because it’s not looking at the anatomy.  It’s looking at the physiology.  Is there anything on the horizon that could replace mammography?

Nancy Evans:    Apparently there is research going on in a couple of places for a blood test that would detect breast cancer before a lump even forms but it hasn’t been made a research priority and it really needs to be. 


BHP:    How much radiation exposure with ultrasounds?  We’re hearing that ultrasounds are better.  Especially that whole question of women under 50.

Nancy Evans:    Well, there is no radiation exposure with ultrasound.  So it is useful in combination with something like MRI for younger women who may come from high-risk families.  Ultrasound works by sound waves rather than X-rays and so there is no radiation involved. 

    But it has to be used with something else.  An ultrasound can tell you if there is fluid in a lesion. Let’s say you found a lump and an ultrasound will tell you if there’s fluid in there.  If there is fluid, it’s probably not cancer, which is really a good thing. 

    But to find out exactly what’s going on you should couple that with MRI and then there’s no way to be absolutely sure whether it’s cancer or not except to do a surgical or a needle biopsy.


BHP:    So a blood test is a possibility in the future. – what about ductal lavage?

Nancy Evans:  Well, that’s being tested and it may tell us something.  It’s not what I would call a benign test.  I haven’t had it but I understand that it can be fairly painful.  

    You would find women much more compliant I think with a screening procedure that is not painful.  And we also have to keep in mind that radiation exposure interacts with chemicals in the environment which increases the risk of harm.


BHP:    Is that like saying that the radiation could potentially damage the gene and then combined with the chemical that further damages the gene?

Nancy Evans:  That’s possible.  I know that in treating certain cancers, doctors like to use radiation and chemo in combination because of radiation potentates the action of the drug which means that the same thing can happen unintentionally if you’re exposed to both radiation and chemicals.  And usually we’re exposed to chemical mixtures rather than one chemical at a time as you can do with lab animals.


BHP:    Of the chemicals that are linked to breast cancer, what are some of the more strongly linked chemicals and how do people get exposed to them?  Is it only for women who work in industry or –

Nancy Evans:     No.  Petrochemicals, that is, chemicals made from petroleum, are the basis for products that absolutely fill our lives.  If you think about cosmetics and personal care products, perfumes, pesticides, plastics, water pipes, computer chips, paints, medicine, carpets, clothes, luggage, furniture and diapers, all of those things are based on chemicals that originate from a barrel of oil.  And oil comes from the fossilized and liquefied bodies of animals and plants. 

    So if you think about the way Sandra Steingraber explains this in the film Rachel’s Daughters, she says that these chemicals are “just enough like us to react with our hormones, stick on to a piece of DNA, etc.  But they’re just enough different from us so we can’t break them down and excrete them.”  So they stay in our bodies for a long time and those are really some of the most treacherous chemicals.  Because we carry them around for a very long time.


BHP:  And those are fat-soluble chemicals?  They go to our fatty tissue like breast tissue?

Nancy Evans:   Right.  And this is particularly worrisome for women of childbearing age because many of those chemicals will also cross the placenta and I’m thinking now of bisphenol A which is a synthetic estrogen that is a component of plastic. 

    And we know from animal evidence that bisphenol A interferes with the development of the mammary gland and as well as other organs and systems.  It’s in the polycarbonate plastic that they make water bottles from and also some baby bottles. (see our guide to plastics here)


BHP:   That’s No. 7.  Right?   The plastic bottle that has the No. 7 on the bottom of it.

Nancy Evans:    I think so.  And it’s also used to line food cans.  Bisphenol A is a high production volume chemical.  Globally there is more than six billion pounds of it produced every year.  And when it’s heated it can leech into food products including baby formula.  And once it’s in food it can move into people. 

    Researchers at CDC have found that bisphenol A occurs in 95 percent of the urine samples they tested and it’s also been found in umbilical cord blood and placental tissue.  Which is really frightening. 


BHPBecause being exposed to a chemical like that in utero or at such young age is actually a big factor in developing cancer later in life.  Isn’t that true?

Nancy Evans:    Exactly.  That’s very true and not just cancer.  I mean we now know that bisphenol A alters brain function and alters behavior and it has a number of effects that are not desirable.  So I would say that bisphenol A is a factor in the later development of cancer.. 

    There are other chemicals such as ethylene oxide, vinyl chloride, butadiene, and benzene.  All of them are known to cause mammary tumors in animals.  All are known carcinogens and they’re just a few of the thousands of chemicals in use today.


BHP:     Now with those chemicals that you mentioned as opposed to something like the bovine growth hormone that they’re putting in milk, what’s the – is there even a comparison to how dangerous some of those are?

Nancy EvansWe don’t really know.  I mean you get a lot of exposures through food and our food supply has definitely been compromised by the addition of bovine growth hormone to milk and other dairy products and also by the way that cows are raised.  I mean they’re pregnant all the time just about. 

    They get about – I don’t know how much time but it’s not a very big window of time before they’re impregnated again so that that milk is – even if it’s organic – is filled with high levels of estrogen from the pregnancies.  So dairy products are a big question mark now in terms of how much you should have.  And since kids are the ones who drink milk, it’s really worrisome. 

    And of course we now have hormones used in beef cattle and that’s worrisome too.  And then we have all of the food that’s processed and canned in cans lined with bisphenol A.  So our food supply has really been quite corrupted.


BHP:    So how do you go about avoiding?  I mean it’s like it’s in the food.  It’s in our cosmetics.  It’s in the carpets.  How do you avoid being exposed continuously to these contaminants?  Is there any way or is there any strategies that people can use?

Nancy Evans:   Well, there are a number of things people can do individually and also collectively.  In terms of individual things, you can do what we call healthy purchasing.  If you can afford it, eat organic and that includes organic milk and meat (if you’re not a vegetarian). 


Eating organic is not only healthier for you and your family, it’s healthier for society because it supports organic farming as a way of growing food and the more people who buy organic, the lower the cost of organic food will become.

    And then eating low on the food chain even if you can’t eat organic.  If you eat primarily a plant-based diet, that lowers your exposure to dioxin which is found in all animal products. 

    And then you can choose cosmetics and personal care products from the 500 companies that have signed the Compact for Safe Cosmetics.  And I’ll tell you more in a minute about where that information is because those companies are making cosmetics out of plant-based non-petrol chemical ingredients so that they’re safer to use. 

    And then replacing toxic household cleaners with cheaper, non-toxic alternatives.  Things like baking soda and Borax soap and vinegar. 

    Eliminating the use of toxic pesticides and herbicides in or around your home.

    Not smoking.  I mean we now have evidence that secondhand smoke is a major risk factor for pre-menopausal breast cancer so not smoking is a really good thing to do for a whole host of reasons.  And not being around people who do smoke. 

    Minimizing your use of plastics and not ever, ever heating anything in plastic.  Because microwave safe means that the heat won’t melt the plastic cookware but it doesn’t mean the food will be safe for you to eat. 

    And then really important and this is back to radiation again, just to avoid unnecessary radiation because the radiation damage to genes is cumulative over a lifetime.  So a lot of low doses can have the same effect as a single high dose.


BHP:   May I ask you a question about radiation?  A lot of doctors tell women that getting a mammogram is about the same as flying in a plane.

Nancy Evans:  Well, that’s really not accurate.  I’ve had that kind of an answer myself when having a radiologic procedure.  ‘It’s like flying to Denver.’  But it isn’t.  It’s way more than a single airline flight.  As we say in State of the Evidence, an average radiation dose of one RAD to the breast is equivalent to the radiation that you would get during 3,300 hours of flying.


BHP:   That’s a lot of flights to Denver.

Nancy Evans:    Yeah.  So a typical mammogram of 0.2 RADs would equal the radiation dose received by the breast in 660 hours of flying.  Not a single trip. 


BHP:    And that’s straight to the breast.  Not to the whole body.

Nancy Evans:    Right.  So it’s very revealing to ask about the dose of radiation when you’re going to have a procedure because you get answers like ‘it’s like flying to Denver’ or ‘I don’t know that but I should.’ Or ‘well, it’s just a really low number.’


BHP:    It must be safe or they wouldn’t let us do it.

Nancy Evans:   Right. 


BHP:     Okay.  I didn’t mean to interrupt you when you were talking about avoiding radiation.  Is there other things that people can do?

Nancy Evans:    Well, I think that when you have an X-ray or a scan you should always be sure to request a lead shield to protect whatever areas of your body are not being X-rayed.  I mean most dentists’ and doctors’ offices are pretty good about that but it just pays to always be sure that you’re shielded.  If you have dental X-rays that you get the thyroid collar that shields your neck when they’re X-raying your teeth, for example.

    And there are other actions you can take if you go to the Breast Cancer Fund web site which is  And there’s an action card there that you can use as a reminder.


BHP:    you can download that card by clicking here

Nancy Evans:    And then those are things you can do as an individual.  But we really need to work collaboratively on this and so one of the things you can do is advocate for safe cosmetics.  We know that chemicals linked to cancer and birth defects don’t belong in cosmetics and personal care products but they’re there.  Especially in popular brands of shampoo and deodorant and face cream. 


    And the European Union has forced companies such as L’Oreal and Revlon and Estee Lauder to eliminate these ingredients in the products they sell in the EU.  But the companies are still refusing to do that in the US.  Breast Cancer Fund believes we all have a right to safe and healthy personal care products and that’s why we’re a founding partner in the Campaign For Safe Cosmetics. 

    And you can go to to find out more.  To check out the products that you’re using and if they’re not as safe as they might be, you can find safer alternatives.

    You can advocate for clean air.  You may be able to control the air in your home but once you step outside all bets are off.  Which is why we all need to work on cleaning up air pollution.  Because the soot and fumes that are released by factories and automobiles and diesel trucks and tobacco products all contain chemicals that are called polycyclic aromatic hydrocarbons or PAHs.  And those are linked to breast cancer and also to other diseases such as asthma.  So you need to advocate smoke-free workplaces and public spaces. 

    And then just speak up and speak out on these issues.  The Breast Cancer Fund has a wonderful leadership development program called Strong Voices and it’s a nationwide group of people who understand the issues and can talk about it and help spread the word.  Tell your friends what you learn about environmental links to breast cancer and advocate for legislation that will protect our environment and our health. 


    You can do a lot to reduce your own exposure to toxic chemicals and radiation but if we’re going to protect the health of the public and future generations, we all need to work together to change how chemicals are regulated in this country.  We need to find safer alternatives for hazardous chemicals and we need to demand research on the safety of new chemicals before they’re allowed on the market.  Not after. 



BHP:    The precautionary principle.

Nancy Evans:   That’s the one.  And then we need also just to keep in mind that timing is everything.  You’ve heard that expression before but in terms of health, timing of exposure is really critical.  The younger you are, the more likely you are to be hurt by environmental exposures whether it’s chemicals or radiation.  And as you mentioned earlier, babies in the womb are at the highest risk.

    And the newest science is showing us that low dose exposure--in parts per billion or even parts per trillion if it’s during a critical window of development--it can cause permanent damage and we know that this is true.  We have not only animal evidence but we have human evidence and it’s evidence that was gained at tremendous human cost. 

I’m thinking of the daughters of women who took the synthetic estrogen DES – Diethylstilbestrol– during pregnancy.   These daughters developed a rare vaginal cancer and other reproductive abnormalities and their mothers developed breast cancer more than other women their age and research is now showing that the daughters have a high risk of breast cancer as well.


BHP:    Those daughters are just getting to the sort of menopausal ages where they’d be more likely to be developing breast cancer.

Nancy Evans:    Right.  And between 1941 and 1971 DES was prescribed for women to prevent miscarriage and not only did it not prevent miscarriage but it did transgenerational damage to the offspring and it affected somewhere between three and six million women in the United States.

BHP:   Nancy, that’s 30 years!!!!

Nancy Evans:  Thirty years.  And scientists knew going in that DES was a hormonally active drug because it had been used in poultry and the male poultry workers were developing breasts.  So clearly something was going on and DES was aggressively promoted and prescribed for pregnant women. 


BHPNow this is still being used in Mexico and India as I understand it.  You still have that chemical being used with women.

Nancy Evans:  That’s shocking.  I was not aware of that.  But we have bisphenol A which is another synthetic estrogen and it’s terrible stuff and it’s just everywhere. 


BHP:   There is a book about this called Hormonal Deception.  It is a depressiong book, but one thing i really appreciate in her book is evidence for detoxification. Are you familiar at all with anything that helps to remove the chemicals from the body?

Nancy EvansI’m not.  I wish I were.  I feel like I’m probably a walking, talking toxic waste site myself, having lived through the DDT era and all these years since.  CDC has found upwards of 150 chemicals and I think the new report which is due out some time this year will find more than 200 in bodies of Americans of all ages and the scary thing is that things like DDT are found in teenagers born after the pesticide was banned in the 1970s so you know it’s coming through their mother’s body into them. 


BHP:   Wow.  Because the mother pretty much dumps her toxic load into that first baby.  I know that they don’t often publish it.


Nancy Evans:   Right.  And even if she doesn’t breastfeed, the stuff has gone through the placenta.  Breastfeeding really helps to mitigate the toxic placental exposures that occur during fetal life so women should really continue to breastfeed even though breast milk is more contaminated than it was when I was a baby.


BHP:     It’s such a pleasure to be working with you at the Breast Cancer Fund.  To be working with people who are talking about prevention is such a wonderful thing because early detection is not prevention.

Nancy Evans:    No, it’s not.  And especially when you’re detecting with something that you know has the potential to cause cancer.  I agree with you.  I think unless we act to reduce exposures that research indicates are increasing our risk, that we’re just going to keep putting more breast cancers in the pipeline and the treatments too often fail. 

    I mean you think if you undergo extreme treatment that is painful and disrupts your life that surely it’s going to work.  And it does work for some people but it fails others and so to have harsh, primitive treatments and not try to prevent the disease in the first place just seems all out of whack to me. 

    And there are lots of organizations using lots of resources to try to find a cure for breast cancer and I would be thrilled if someone came up with a cure for breast cancer because I’ve lost more than 25 friends to this disease.  But I don’t want my granddaughter to have it.  And I don’t want anybody’s granddaughter to have it

    And it’s not just breast cancer.  I mean the cancer risk in this country is now one in three for women and one in two for men.  And cancer is not the only thing that is going wrong with our bodies.  I mean if you look at the incidence of chronic disease, it’s overwhelming. 


BHPRight.  Well, the insulin metabolic syndrome, all those things that now they’re starting to link to the same contaminants.

Nancy Evans:            Right.  Bisphenol A is one of them.


BHP:   In my clinical practice I’m seeing younger and younger women getting breast cancer and I realize that you don’t see the numbers really change for a few years until the statistics come in but are younger women getting more breast cancer?

Nancy Evans:     Well, in the circles that I travel in, the anecdotal evidence would say yes indeed.  But the official numbers don’t reflect that.  I mean if you look at trends over time it looks like a flat line.  And they say, well, there are just more women in the age group, the pre-40 age group, and therefore it looks like there’s more breast cancer but the rate per 100,000 hasn’t changed.’

 But I don’t know if I believe that or not.


BHP:   Is there anything else that you want to be sure to communicate to the people from the Breast Health Project?

Nancy Evans:    Just that we need to not only work on individual actions but collective actions that will protect public health from these toxic environmental exposures.

Thank you, Nancy Evans!

Nancy Evans, BS, is a health science writer and editor with more than three decades of experience in healthcare publishing.

Diagnosed with breast cancer in 1991, Evans became a leader in the grassroots breast cancer movement, serving as president of Breast Cancer Action (BCA) and editor of the BCA newsletter. During 1998 she served on the board of The Breast Cancer Fund, and she currently works with The Fund as communications consultant.

Evans is co-producer (with Allie Light and Irving Saraf) of the 1997 documentary, Rachel's Daughters: Searching for the Causes of Breast Cancer.

Evans has written and spoken extensively on breast cancer issues for audiences in the United States, Canada, Belgium and New Zealand. She co-chaired one of six working groups in the National Action Plan on Breast Cancer and served as an Oncology Patient Fellow at the Food & Drug Administration.

Evans is co-author (with Andrea Ravinett Martin) of The Breast Cancer Fund's Pathways to Prevention: Eight Practical Steps--From the Personal to the Political--Toward Reducing the Risk of Breast Cancer, published in March 2000.




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