the National Toxicology Center
at the National Toxicology Program:
Mr. Bill Grigg, 301 402-3378
Ms. Sandra Lange, 919 541-0530
NATIONAL TOXICOLOGY PROGRAM CENTER FOR THE EVALUATION OF RISKS
TO HUMAN REPRODUCTION
EXPERT PANEL REVIEW OF PHTHALATES
NTP Center for the Evaluation of Risks to Human Reproduction (CERHR):
line with the National Toxicology Programís goal to provide toxicological
evaluation on substances of public health concern, the NTP and
the National Institute of Environmental Health Sciences established
the CERHR to provide scientifically based, uniform assessments
of the evidence for reproductive and developmental toxicity of
man-made or naturally occurring chemicals or chemical mixtures.
The first major step in the Centerís evaluation of seven phthalate
esters was completed in Arlington, Virginia, on July 12-13 when
an expert panel concluded their deliberations on the phthalates.
of Phthalate Esters:
esters are used as plasticizers in a wide range of polyvinyl chloride-based
consumer products. These phthalate esters were selected for the
initial evaluation by the CERHR based on their high production
volume, extent of human exposures, use in childrenís products,
or published evidence of reproductive or developmental toxicity.
panelís deliberations focused on the amount and quality of data
available in two primary areas, human exposures to these phthalates
and experimental evidence for their reproductive and developmental
toxicity. Working over a 15 month period, the panel assigned "low,
minimal, or negligible concern" for five of the following agents
and higher concern for only one, di (2-ethylhexyl) phthalate or
di(2-ethylhexyl) phthalate (used in building products,
food packaging, childrenís products and medical devices) there
was "serious concern" for the possibility of adverse effects on
the developing reproductive tract of male infants exposed to very
high levels of DEHP that might be associated with intensive medical
procedures such as those used in critically ill infants. The Panel
recognized the health benefits of these procedures. There was
"concern" that exposure of pregnant women to current estimated
adult exposure levels of DEHP might adversely affect the development
of their offspring. The Panel expressed "concern" that, if infants
and toddlers are exposed to levels of DEHP substantially higher
than adults, adverse effects might occur in the developing male
reproductive tract. The Panel expressed "minimal concern" that
current exposures of adults to DEHP would adversely affect the
di-isononyl phthalate (used in garden hoses, shoes/shoe
soles, toys, construction materials), the Panel expressed "minimal
concern" for adverse developmental outcomes resulting from exposure
of pregnant women and "minimal concern" for adverse effects on
the reproductive system of exposed adults. There was "low concern"
for potential health effects in children who might be exposed
to DINP through the mouthing of toys or other DINP-containing
objects. The Panel expressed "minimal concern" for the potential
developmental effects that might result from exposure of pregnant
women or children to di-isodecyl phthalate (used in automobile
undercoating, wires and cables, shoes, carpet backing, pool liners).
Likewise, there was "minimal concern" for effects on the reproductive
systems of adults exposed to DIDP.
di-n-butyl phthalate (substances used in latex adhesives,
cellulose plastics and solvent for dyes), the Panel expressed
"minimal concern" for potential effects on human development,
including effects on the developing male reproductive tract, and
"negligible concern" for effects on the reproductive systems of
exposed adults. The data available on butyl benzyl phthalate (used
in vinyl tile, food conveyor belts, artificial leather, traffic
cones) led the Panel to express "negligible concern" for effects
on adult male reproduction. Developmental effects were noted but
conclusions could not be drawn.
di-n-octyl phthalate (used in the manufacture of flooring
and carpet tile, canvas tarps, notebook covers) the panel expressed
"negligible concern" for effects on the human reproductive system
and "minimal concern" for adverse developmental effects resulting
from exposure during pregnancy or childhood.
were too few data available on di-n-hexyl phthalate (used
in automobile parts, tool handles, dishwasher baskets, flooring,
tarps, flea collars) for the Panel to reach any conclusions.
COMPLETION AND DISTRIBUTION
Expert Panel report will be completed and provided to the scientific
and public communities for review by October 2000. The National
Toxicology Program and the CERHR will solicit public comments
for a period of 60 days. As part of its own report, the NTP will
transmit the Expert Panel Report, the public comments received
on the expert panel report, and any newly available information
since completion of the expert panel report to the appropriate
Federal and State Agencies, the public and the scientific community.
A special effort will be made to prepare the summary in language
that can be understood by those who are not scientifically trained.