ACSH
AMERICAN COUNCIL ON SCIENCE AND HEALTH
Review and Consensus Statement
A Scientific Evaluation of Health Effects of Two Plasticizers Used in Medical Devices and Toys
C. Everett Koop, MD, ScD; Daland R. Juberg, PhD; Elissa P. Benedek, MD; Ronald W. Brecher, PhD, C Chem, DABT; Robert L. Brent, MD, PhD; Philip Cole, MD, DrPH; Morton Corn, PhD; Vincent Covello, PhD; Theron W. Downes, PhD; Shayne C. Gad, PhD, DABT; Lois Swirsky Gold, PhD; F. Peter Guengerich, PhD; John Higginson, MD, FRCP; W. Hans Könemann, PhD, RIVM; James C. Lamb IV, PhD, DABT; Paul J. Lioy, PhD; George D. Lundberg, MD; Kimberly M. Thompson, ScD
More information on the authors and editors
[MedGenMed, June 22, 1999. © Medscape, Inc.]
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Executive Summary
Recently, public concern has been raised regarding possible health hazards of di(2-ethylhexyl) phthalate (DEHP) and diisononyl phthalate (DINP), two chemicals that are used as plasticizers in flexible vinyl products. DEHP is the primary plasticizer used in many medical devices, whereas DINP serves a similar function in soft vinyl toys that may be mouthed by young children.
The American Council on Science and Health convened an independent expert panel to evaluate the scientific evidence regarding potential health risks associated with DEHP and DINP and to identify areas of uncertainty or data gaps in the information available on these substances. The Panel reviewed source information that forms the basis for concerns about human health effects of DEHP and DINP. A wide variety of documents were examined, including primary and secondary scientific literature, risk assessments published by regulators in the US, Canada, and Europe, and scientific manuscripts still in preparation.
In conducting a risk assessment, there are always uncertainties and assumptions, and hence, it is impossible to state that there is no risk from exposure to a given substance. The same observation is applicable to the vast number of chemicals that occur naturally and to which humans are exposed. However, a risk assessment that considers and utilizes the weight of scientific evidence can minimize uncertainty about potential human risks. Accordingly, the conclusions of the Panel are based on (1) scientific data and analysis indicating that DEHP and DINP are not genotoxic, that an exposure can be estimated below which effects are unlikely to occur, and that there are critical differences between the toxicology and mechanisms for these chemicals between rodents and humans, and (2) measurements or estimates of human exposure to these chemicals.
The Panel concludes that DEHP in medical devices is not harmful to even highly exposed people, those who undergo certain medical procedures such as regular hemodialysis or extracorporeal membrane oxygenation (ECMO). Furthermore, the Panel concludes that DEHP imparts a variety of important physical characteristics that are critical to the function of medical devices, and eliminating DEHP in these products could cause harm to some individuals. Any substitute for DEHP or DEHP-containing medical devices should be evaluated using the same criteria as used for DEHP: (a) demonstrated suitable physical characteristics and function in critical medical device applications, and (b) risk assessment based on studies of animal and human toxicology and human exposure data.
The scientific literature on DINP is less voluminous than that on DEHP. Although results of animal toxicity tests suggest the need for thorough evaluation, the Panel concludes that much of this evidence has little relevance for humans and that DINP in toys is not harmful for children in the normal use of these toys. To expand our knowledge of child exposure to DINP from toys, the Panel recommends that further studies be undertaken to document (a) children's contact time and mouthing behavior with toys and other objects, and (b) rates of release of DINP under realistic conditions. This would improve the precision of exposure estimates for DINP, and would also be of benefit in evaluating exposures to other substances in toys or objects mouthed by children. Any substitute for DINP or DINP-containing flexible toys should be evaluated for potential risks based on animal and human toxicology data and human exposure data.