This study recently published in Environmental Health Perspectives, the monthly peer-reviewed journal supported by the National Institute of Environmental Health Sciences, National Institutes of Health, and the U.S. Department of Health and Human Services, concluded that phthalate exposure in the U.S. has changed. Researchers analyzed urine samples taken between 2001 and 2010 from more than 11,000 American adults and children enrolled in the CDC’s National Health and Nutrition Examination Survey (NHANES). From them, they observed that people are still widely exposed to phthalates, with some phthalates found in 98% of all urine tested. But as the table below shows, half of the phthalates tested went up in prevalence and half went down.
The question is why? 
The study’s authors — Ami Zota of the George Washington School of Public Health, Tracey Woodruff of UC San Francisco, and Antonia Calafat of the Centers for Disease Control and Prevention — postulate that “legislative activity and advocacy campaigns by non-governmental organizations may play a role.”
Phthalates are used as a plasticizer. Those with low molecular weight, like DEP, DnBP, and DiBP, are used in personal care products, solvents, adhesives, and medications. High molecular weight phthalates, like BBzP, DiNP, DiDP, and DEHP, are used in polyvinyl chloride (PVC) used in building materials, cables and wires, toys, and packaging. Many phthalates have been linked to a variety of health effects via animal tests and some human studies, including hormon disruption, male reproductive abnormalities, and impaired behavioral development.
In response to these studies, Congress banned three compounds used in U.S. toys
and other children’s products in 2008: DEHP, DnBP, and BBzP used in an amount greater than .1% . In that same statute, Congress also placed interim restrictions on DiNP, DiDP, and DnOP used in toys that can be put in a child’s mouth.
Zota et al. found that the presence of these three banned phthalates dropped significantly from 2001 to 2010. DEHP decreased 37%; DnBP (used in nail polish until a few years ago) dropped 17%; and BBzP (used in vinyl tiles and sealants) decreased 32%. DEP (used mostly for fragrance) decreased 42%; it was not banned by Congress but instead subject to removal pressure by
advocacy groups like the Campaign for Safe Cosmetics.
That is the glass half full – er, I mean empty? – story of the last decade of U.S. phthalate exposure.
The flip side of this study shows that three other phthalates used in some children’s products increased during this same time period: DiNP rose 149%; DnOP, 25%; and DiDP, 15%, even though they were subject to the interim restrictions. Last month, California added DiNP to its list of known carcinogens, which could lead to warning labels on consumer products sold in the state using it.
While researchers believe that the downward trend is a byproduct of the federal law and
consumer advocacy, they suspect that the upward trend may result from manufacturers substituting new phthalates for the banned ones. Because listing ingredients isn’t required on many consumer products, they can’t prove this hypothesis by studying product labels. But data from the European Chemical Agency documents that DiNP and DiDP are taking the place of DEHP, totaling 30-60% of the current U.S. and EU plasticizer market.
Bottom line: “There’s a clear need for better data reporting on ingredient composition of everyday consumer products so that we can fully understand the impacts of legislation and consumer pressure.”
UPDATE: This just in from the Left Coast: Deluxe Corp., “America’s best-known check brand” (with 4 million small business customers and 6,200 financial institution clients), settled a suit brought under California’s Prop 65 alleging that its product contains DEHP. As part of the settlement, Deluxe will pay up to $135,000 in fines, with a portion waived if the company meets a June, 2015 deadline certifying that it at has reformulated at least 90% of its checkbook covers.