Lindsay McCormick is a Research Analyst. Richard Denison, Ph.D., is a Lead Senior Scientist.
A recent study published in Environmental Health Perspectives is the first to demonstrate a link between childhood asthma and prenatal exposure to certain phthalates. Phthalates are a group of chemical plasticizers used in hundreds of everyday products, including home construction materials, toys, food packaging, medical devices, and synthetic fragrances found in personal care products, cleaning products, cosmetics, and air fresheners. For the most part, it is impossible for the average consumer to know what products are made with phthalates; however, if you see the word “fragrance” listed on your shampoo or sun screen, it may well contain a phthalate.
Several studies have suggested that phthalate exposure may have an adverse impact on children’s respiratory health (for example, see here, here, and here). However, none of these studies has considered the potential role of prenatal exposure – exposures to the fetus in the womb – to phthalates.
The prenatal period is a critical developmental window for lung and respiratory health. Thus, researchers at the Columbia Center for Children’s Environmental Health (CCCEH) hypothesized that prenatal phthalate exposure would be associated with later development of asthma in childhood. To investigate this hypothesis, the researchers measured phthalate metabolite levels in the urine of 300 women in the 3rd trimester of pregnancy, and then followed the children of these women to assess the extent to which they developed asthma between the ages of 5 and 11.
The study demonstrated that risk of developing asthma in childhood was more than 70% higher in those children exposed prenatally to high levels of two specific phthalates—butylbenzyl phthalate (BBP) and di-n-butyl phthalate (DBP)—relative to those with low levels of exposure. This study expands on earlier research conducted by the same group that found an association between exposure to certain phthalates and a marker of airway inflammation in childhood.
Although the evidence linking prenatal phthalate exposure to asthma is just emerging, an association has long been recognized between prenatal phthalate exposure and toxicity to the male reproductive system. A growing body of evidence indicates that prenatal phthalate exposure can cause male infertility by dysregulating androgenic hormones such as testosterone during development of the reproductive tract. This science reinforces the view that fetal development is the period of highest vulnerability to phthalate exposure.
Dearth of regulation
Despite mounting evidence linking phthalate exposures to health impacts, regulation of phthalates remains limited.
Regulatory authority over phthalates is dispersed across a number of federal agencies and further segregated by product type. While many products that contain phthalates, including cosmetics and other personal care products, food packaging, and medical devices, fall under the regulatory authority of the Food and Drug Administration (FDA), their use in most of these products does not require premarket safety approval by FDA. For example, under the Federal Food, Drug, and Cosmetic Act (FFDCA), FDA can only take action against cosmetics after they are on the market and where FDA has obtained “dependable scientific evidence” indicating that the product is unsafe. FDA’s current stance is that there is not sufficient scientific evidence to take regulatory action against phthalates in cosmetics.
Other types of consumer products containing phthalates, such as polyvinylchloride (PVC) piping or windows, fall under the Environmental Protection Agency’s (EPA) regulatory authority. Although EPA has recognized the potential health risks posed by certain phthalates, it has not successfully implemented regulation to limit consumer exposure. In 2010, EPA proposed a rule to add eight phthalates, including BBP and DBP, to its “chemicals of concern” list, but retracted the proposed rule in 2013 after it sat awaiting White House approval for three years. EPA has, however, enlisted its Design for the Environment program to review alternatives to phthalates through a non-regulatory approach.
Ban in children’s products
In the face of regulatory inaction by federal agencies, Congress took the first step in 2008. The Consumer Product Safety Improvement Act (CPSIA) permanently banned three phthalates (BBP, DBP, and DEHP) and placed an interim ban on three additional phthalates (DINP, DIDP, and DNOP), when present in an amount greater than 0.1% in children’s toys and child care articles. CPSIA also required the U.S. Consumer Product Safety Commission (CPSC) to convene a Chronic Hazard Advisory Panel (CHAP) to evaluate the potential for children’s health effects from phthalates and their alternatives. In July of this year, the CHAP on Phthalates and Phthalate Alternatives recommended several additional permanent and interim bans, as well as the lifting of the interim ban on DNOP and DIDP in children’s toys and child care articles.
While this action reflects recognition of the risk that phthalates pose to children, it places the intervention point too late in the process of child development. That’s because the science tells us that the most vulnerable window for phthalate exposure is during early development, in the womb. This means that by the time a child picks up a chew toy while s/he’s teething, it may already be too late to avoid many of the potential health effects of phthalate exposure.
Instead, additional focus needs to be on reducing exposures to pregnant women and women of reproductive age. The CHAP report indicates that the major sources of phthalate exposures in this population are diet, pharmaceuticals, personal care products, and contamination in the indoor environment. The largest sources of exposure to the phthalates discussed in the CCCEH study, BBP and DBP, for women are aerosol paints and nail polish, respectively.
Thus, if we are to prevent prenatal phthalate exposure, an expansion of regulation to a variety of everyday products women use needs to be considered. This does not mean that exposures during childhood needn’t also be addressed; childhood continues to be a vulnerable window of development and exposure during this time may very well lead to harmful health effects.
Existing bans may not even be sufficient to prevent childhood exposure, however: the CHAP report found that the largest source of phthalate exposure in infants and toddlers is from food and beverages, not from child toys and child care products.
Need for a comprehensive regulatory solution
In sum, selectively banning phthalates from children’s toys and child care articles – the only regulatory action taken so far – creates a false impression of adequate public health protection. It fails to address the key concern of prenatal exposures and is insufficient to prevent childhood exposure.
A more comprehensive regulatory solution is needed that systematically reviews all phthalates – both individually and in combination – and considers all potential sources of exposure in order to make safety decisions.
The CHAP recognized the limitation of regulating only children’s products in its report. Along with permanent and interim bans in children’s products, the CHAP recommended that the federal agencies responsible for addressing exposures to these phthalates from other products conduct appropriate risk assessment and risk management strategies.
Will EPA and FDA step up and respond to the CHAP’s recommendation?
2 Comments
This is a very important point that HBN has also explored in our recent report on asthmagens in building materials (Full Disclosure Required: A Strategy to Prevent Asthma Through Building Product Selection http://www.healthybuilding.net/content/research-and-reports).
In that study, we identified twenty top-priority asthmagens in nine chemical group that are widely used in building materials and have high likelihood of occupant exposures, including but not limited to the phthalates discussed here. We found evidence that that numerous of these can impact children in utero and/or in children’s early critical years of development setting the stage for the later emergence of asthma.We further found that green building material certification protocols intended to insure good air quality do not address these chemicals linked to the onset of chemicals.
Given the challenge of measuring emissions of many of these chemicals and a lack of science confirming safe thresholds, our conclusion is that the only reliable asthma protective policy for building materials is avoidance of select top priority asthmagens.
Thank you, Tom, for your comment. Contaminants in the indoor environment are certainly a major source of exposure to certain phthalates. You raise a very important point that there are many chemicals used in building materials, in addition to phthalates, where there is evidence linking prenatal and early life exposure to asthma. It’s great to see from your report that in the absence of adequate regulation and building product Indoor Air Quality (IAQ) certification systems, HBN has provided a publicly available source identifying safer building products that do not contain these chemicals through The Pharos Building Product Library (https://www.pharosproject.net/product/).