A primary mission of the Phthalate Esters Panel is to identify and support lines of research that will tell us more about the environmental and health effects of phthalates. In its thirty-plus years of existence, the Panel has supported millions of dollars of research with funds contributed by its member companies. By working together, the member companies of the Panel have been able to bring together experts to develop and implement important and often cutting edge research, in many cases developing techniques to address issues when they first surface. The Panel has joined with companion trade groups in Japan and Europe to support major investigations, such as the $1 million study recently completed in Japan on the effect of DEHP on primates. The Panel has also supported research requested or suggested by government regulatory agencies.
Management of the research is carried out by two subgroups of the Panel, the Toxicology Research Task Group (TRTG), and the Environmental Research Task Group. These groups are peopled by toxicologists and environmental scientists from member companies or from outside consulting firms hired by member companies. The research, generally contracted for and carried out by independent laboratories in the private sector or in academia, is typically published in peer-reviewed journals. Publications describing the various research programs supported by the Panel are included in this section of the Web site. Apart from work sponsored by the Panel, phthalate producers individually also have undertaken a number of studies of phthalates. References to some major pieces of research sponsored by phthalate producers are also included in this section of the Web site.
In their half century of use, a great quantity of research has been conducted on phthalates, not only by industry but also by universities, government agencies, and independent laboratories. This body of research makes phthalates one of the most widely studied and thoroughly characterized family of chemicals in use today. The preponderance of the research has been conducted in animals including rodents and primates, but there is also some more limited data from biomonitoring studies in humans. In addition, some data has been collected in human volunteer studies studying possible sensitization and irritation. Most of the experimental research on potential health effects of phthalates consists of laboratory rodent studies, where a range of doses up to the highest dose animals can tolerate are administered over periods of time from a few weeks to two years. The process the government generally uses to apply data from these rodent studies to humans is to find the highest dose that has no effect on the animals,(called a NOAEL for “no observed adverse effect level”), and then to divide by a safety factor ranging from 100 to 1,000 to establish safety levels for human exposure. The daily human exposure levels and government safety levels for the major phthalates can be found here: Human Exposure and Biomonitoring.
Because there is such a huge body of research on phthalates, it is difficult to come to any conclusions about their safe use by looking at a few selective studies. Fortunately, comprehensive reviews of the major phthalates have recently been conducted both in Europe and the United States. The U.S. National Toxicology Program has issued final reports on six of the seven phthalates it reviewed, and found that, in most cases, the risk to human reproductive and developmental health is “minimal” or “negligible.” The reports can be found here: CERHR Publications. One review remains to be finished The European Union has published risk assessments for two phthalates, which found no need for further information and/or testing and for risk reduction measures beyond those which are being applied already. The EU is completing risk assessments on three other phthalates.
Environmental research conducted by industry and others has led to a scientific consensus on two key points. First, phthalates are not persistent; they are quickly biodegraded in water and soil. Second, bioaccumulation and biomagnification are also not concerns; living organisms do not build up levels of phthalates over time, but break them down and eliminate them quickly.
The Panel’s task groups and other industry groups are still pursuing lines of investigation to further illuminate the possible effects of phthalates on living organisms and the environment. Due to past research, initial questions about the possible cancer-causing effects of some phthalates have given way to the scientific consensus that the effects are peculiar to rodents, and not relevant to humans. A current line of inquiry seeks to explore the suggestion from recent research with primates that reproductive effects seen in rodents likewise may not be relevant to humans. A few experiments remain to be completed concerning possible allergic effects of phthalates, although recent rodent tests examining whether phthalates could cause respiratory allergy have shown no effect, and similar testing for possible allergic reactions in skin has likewise shown no effects. Research continues on the fate of phthalates and their metabolites in the aquatic food chain. The Phthalate Esters Panel welcomes questions about the research it supports regarding phthalates.