- Evidence is mounting that a chemical in plastic may be
risky in the small amounts that seep from bottles and food packaging, according
to a report to be published this week in a scientific journal.
- Authors of the report, who reviewed more than 100 studies,
urged the Environmental Protection Agency to re-evaluate the risks of bisphenol
A and consider restricting its use.
- Bisphenol A, or BPA, has been detected in nearly all
human bodies tested in the United States. It is a key building block in
the manufacture of hard, clear, polycarbonate plastics, including baby
bottles, water bottles and other food and beverage containers. The chemical
can leak from plastic, especially when containers are heated, cleaned with
harsh detergents or exposed to acidic foods or drinks.
- The plastics chemical is the focus of one of the most-contentious
debates involving industrial compounds that can mimic sex hormones. Toxicologists
say exposure to man-made hormones skews the developing reproductive systems
and brains of newborn animals, and could be having the same effects on
human fetuses and young children.
- Since the late 1990s, some experiments have found no
effects at the doses of BPA that people are exposed to, while others suggest
that it is estrogenic, blocks testosterone and harms lab animals at low
doses. Plastics-industry representatives say the trace amounts that migrate
from some products pose no danger and are far below safety thresholds set
by the EPA and other agencies.
- In the new report, to be published online tomorrow in
Environmental Health Perspectives, scientists Frederick vom Saal and Claude
Hughes say that, as of December, 115 studies have been published examining
low doses of the chemical, and 94 found harmful effects.
- In an interview yesterday, vom Saal, a reproductive biologist
at University of Missouri, Columbia, said there is now an "overwhelming
weight of evidence" that the plastics compound is harmful.
- "This is a snowball running down a hill, where the
evidence is accumulating at a faster and faster rate," vom Saal said.
"You can't open a scientific journal related to sex hormones and not
read an article that would just floor you about this chemical. ... The
chemical industry's position that this is a weak chemical has been proven
totally false. This is a phenomenally potent chemical as a sex hormone."
- In their study, vom Saal and Hughes suggest an explanation
for conflicting results of studies: 100 percent of the 11 funded by chemical
companies found no risk, while 90 percent of the 104 government-funded,
nonindustry studies reported harmful effects.
- Steven Hentges, executive director of the polycarbonate
business unit of the American Plastics Council, said yesterday that the
new report lists numbers of studies and pieces of data without analyzing
them to determine their strengths or weaknesses and relevance to human
- "The sum of weak evidence does not make strong evidence,"
Hentges said. "If you look at all the evidence together, it supports
our conclusion that BPA is not a risk to human health at the very low levels
people are exposed to. This paper does not change that conclusion. It has
an opinion, not a scientific conclusion."
- There has been an escalating battle between vom Saal
and the plastics industry since 1997, when vom Saal was the first to reveal
low-dose effects in mice exposed to BPA. His discovery triggered a rash
of new scientific studies by industry and government.
- The chemical, used in polycarbonate plastics manufactured
for half a century, is not subject to any bans.
- Polycarbonate plastics, useful in items such as baby
bottles because they are durable, lightweight and shatter-resistant, cannot
be made without BPA.
- Copyright © 2005 The Seattle Times Company