Not a flower shop: Exploring breast cancer risk and gender bias

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Publication Date: 
Tue, 2012-07-17

Plastics are chemical substances derived from petroleum. Like gasoline, diesel fuel, and asphalt, the raw materials needed to produce plastics are the end products of the distillation of crude oil. Refineries both distill and separate crude into various components, or fractions, which are used to make more than 2,500 substances and chemicals used in home and industry. Acrylonitrile, styrene and vinyl chloride are just three chemicals used in the plastics industry. They are made up of repeating chains of monomers (units of molecules) that are joined together in a process that transforms them into polymer resins, such as acrylonitrile-butadiene-styrene (ABS), polystyrene (PS), and polyvinyl chloride (PVC).

But plastics are not benign substances. Many of them are known carcinogens, mutagens and endocrine-disrupting chemicals (EDCs), substances that interfere with the normal functions of hormones throughout the body and contribute to the development of breast cancer as well as neurological and reproductive disorders. EDCs can have an effect at extremely low doses, in some cases as low as parts per trillion.

“These chemicals that mimic estrogen or other hormones have the biggest effect not at high levels, but at the very lowest levels. If the timing is right, the exposure can be very small, and have the most dramatic effects. None of that has been accounted for at all in these substances, so it’s not just that women in the plastics industry are getting exposed to polyvinyl chloride or acrylonitrile or styrene, which have been shown to be mammary carcinogens in animal studies, it’s that they are getting exposed to chemicals that also mimic estrogen.” – Margaret Keith

The changing lists of ingredients used to manufacture plastics also make it very difficult to know what specifically increases breast cancer risk. Additives, some of which have been historically included in plastics making, metals such as lead and cadmium, plasticizers such as di-ethylhexyl phthalate (DEHP), and flame retardants such as polybrominated biphenyls (PBB) and diphenyl ethers (PBDE), are but a few of the chemicals classified by the International Agency for Research on Cancer (IARC) as either known or possible carcinogens and as endocrine disruptors. Polycyclic aromatic hydrocarbons (PAHs), formaldehyde, and solvents such as benzene and toluene are other chemicals that may also initiate breast cancer and mimic estrogen. Not only that, but the synergistic affect of these chemicals on health in general, and breast cancer in particular, is unknown and could be enormous.

“We have found that so often when we are doing these talks, and even when we’ve been doing focus groups we get people saying ‘Oh my gosh I had no idea that the stuff could be so dangerous. I knew people were getting sick, I knew I had headaches, but I didn’t know it could increase my risk of breast cancer. I didn’t know that these things were estrogenic.’” – Margaret Keith

A plastic world

Plastics fall into two main categories: thermoplastic resins that can be repeatedly softened and reshaped using heat and pressure, and thermoset resins that can be permanently set using a chemical reaction. Both are heavily used in the auto parts industry and undergo various processes to make the dozens of items found in a car, such as seats, dashboards, bumpers, and numerous engine components. These substances arrive at the auto plastics plants in the form of powders, pellets and liquids.

Workers are handling these substances over and over again, absorbing, inhaling and ingesting them via skin, lung and mouth. On any given day a worker may pour these chemicals from bag to container, blend and mix additives, melt resins, and/or force the heated resins into various shapes using processes such as injection moulding, extrusion, blow moulding, compression moulding and calendering. All these processes expose workers to a range of compounds in the form of fumes and gases, smoke and vapours, dust and particulate matter.

“There would be lots of fumes. The safety alarms were shut off. We ran polyvinyl chloride, lead and chromium and silica—all designated substances. And we had no control program… that is why we wanted ventilation. We were told, ‘You don’t work in a flower shop.’” – NNEWH-funded focus group participant

Is it no wonder then that we are seeing an epidemic in breast and other cancers? Women are especially vulnerable to chemical exposure due to their smaller body size, greater amounts of fatty tissue (where toxins tend to accumulate), the sensitivity of their unique hormonal and reproductive systems, and heart function. Women in the plastics plants are putting their health, and lives, at risk.

“We heard about so much more than just breast cancer. There were lots of concerns about breathing problems, and reproductive issues, about miscarriages or infertility. So many of them talked about headaches and sore throats and feeling dizzy or faint. A lot of them talked about how terrible the smell and the smoke was, and sometimes they would have to go running outside to get fresh air if there was some malfunction, which would happen frequently in the process of heating plastics.” – Margaret Keith

New studies connect the dots

Having reviewed the scientific literature on occupation and cancer incidence to date, Brophy and Keith are conducting primary research using worker- and community-based research techniques, including the use of focus groups (where participants describe their personal stories) and hazard mapping (a technique of mapping workplace settings that show how they contribute to disease and other health conditions).

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