(January 8, 2007) -- The Environmental Protection Agency is poised to dramatically weaken the health standard for Dibutyl Phthalate (DBP), a ubiquitous chemical found in toys, cosmetics and other consumer products that can disrupt reproductive and hormonal systems.
Despite growing evidence of DBP’s threat to human health, which has prompted the European Union to ban it in children’s toys and cosmetics, the agency’s proposed new safe exposure level will be three times higher than the current one.
The Natural Resources Defense Council (NRDC) expects the agency to announce the new standard by mid-January.
DBP and other phthalates are widely used to soften plastics and to dissolve chemicals in fragrances, perfumes and hairsprays. DBP also provides an oily texture for skin softeners and makes nail polish chip resistant.
The existing DBP standard, which was written in 1990, was based only on the number of deaths it caused in animal studies. Since then, however, scientists have devised ways to detect more subtle but damaging effects of DBP on both lab animals and humans. Numerous studies have raised serious new concerns, but they were largely ignored by the EPA in its current review process, according to NRDC and other health advocates. In a December 21, 2006, letter to the agency, the organizations urged EPA to recalculate the safety level for DBP.
The imminent new DBP standard is part of a broader and ongoing EPA review of the public health risks of chemicals in the environment.
DBP Poses a Significant Threat to Public Health
DBP interferes with testosterone production and has been linked to underdeveloped or absent reproductive organs, retained nipples, undescended testicles, birth defects of the penis, and decreased and abnormal sperm in male rats. Human studies have found a link between DBP and abnormal sperm, and – in baby boys – decreased testosterone levels and a decreased distance between the anus opening and the urethra opening on the penis. Although these studies were relatively small, the findings are important because they corroborate what scientists are seeing in animal studies, and the subjects experienced exposures to routine, everyday levels of DBP. The EPA did not use these studies when determining its new safe exposure level.
Human exposure to DBP is widespread. For example, a 2004 study by the U.S. Centers for Disease Control and Prevention, found that 99 percent of urine samples from nearly 2,500 Americans had detectable levels of a DBP metabolite (Silva, M.J. et al. 2004. “Urinary levels of seven phthalate metabolites in the U.S. population from the National Health and Nutrition Examination Survey (NHANES) 1999-2000,” Environmental Health Perspectives, 112:331-338). A separate study that same year, involving 54 pregnant women, found a DBP metabolite in 93 percent of the amniotic fluid samples, indicating there is significant exposure during critical periods of fetal development (Silva, M.J. et al. 2004. “Detection of Phthalate Metabolites in Human Amniotic Fluid, Bulletin of Environmental Contamination Toxicology,” 72: 1231).
If the EPA had taken a more precautionary and protective approach in determining the new standard, it would have used all of the available science. Instead, the agency ignored the critical effects of DBP at low levels found in the animal studies and disregarded the epidemiological evidence of the damage it can do to baby boys. Moreover, EPA’s risk assessment should have taken into account the fact that Americans already are routinely exposed to phthalates. This would have resulted in a standard that is more than 3,000 times lower than the previous one and more than 20 times lower than average levels of exposure. Given the enormous amount of new scientific data over the past 16 years on early life exposures, low-dose effects, and gene data, there is no justification for the EPA to propose a higher standard than the previous one.