From: Robina Suwol
Date: 15 Jun 2004
Time: 17:57:38
Remote Name: 68.116.132.61
Fire retardants' effects arouse safety debate
By Stephanie Ebbert, Globe Staff | June 14, 2004
TORONTO -- For more than 30 years, the stuff of American life -- computers
and hair dryers, sofa cushions and auto dashboards -- has increasingly been
built from plastic and synthetics treated with chemicals to slow the spread of
fire.
And at alarming levels, researchers are discovering, those fire retardants are
building up in our bodies as well. A growing body of research shows that the
chemicals, known as polybrominated diphenyl ethers, or PBDEs, are rapidly
accumulating in people's blood, in mothers' breast milk, and in animals as
remote as Arctic polar bears.
Concern about the rising measures of PBDEs has prompted three states and the
European Union to ban two of the three forms of the chemical. Canada just
declared all three forms toxic. But as momentum builds, scientists and
regulators are running into a
nagging knowledge gap: Even the experts haven't proven PBDEs are causing humans
any harm.
Last week, a conference on PBDEs drew nearly 200 researchers and academics from
around the world to share research on the chemicals, which have been shown to
cause reproductive and learning problems in animals. But firm data on human
health effects remain elusive, and epidemiological studies are only now
underway. The US Environmental Protection Agency has been evaluating and funding
research into PBDEs, but has not decided that they pose an unreasonable risk to
health or the environment.
In the absence of firm evidence on human effects, the movement to ban PBDEs is
stoking a long-running debate over possibly toxic chemicals: How much evidence
is needed before the government steps in? Some manufacturers and scientists say
the known benefits outweigh a still-unproven threat, but proponents of the
"precautionary principle" maintain that, in the face of uncertainty, suspect
substances should be deemed guilty before judged innocent.
"By the time we actually do know, we're going to be dealing with 25 or 30 years
of legacy and we can't do anything about it," said Joel Tickner, assistant
research director at the Lowell Center for Sustainable Production, who argues
for banning PBDEs and using safer alternatives.
Used since the 1970s, PBDEs have proved popular with manufacturers because they
can make plastics flame-resistant without turning them brittle or otherwise
changing their properties. "They're the most effective [flame retardants]," said
Peter O'Toole, US
program director for the Bromine Science and Environmental Forum, which
represents the world's three manufacturers of PBDEs.
But scientists are growing increasingly alarmed about PBDEs because of their
chemical similarities to a more famous family of chemicals largely banned a
generation ago that continue to permeate the environment -- polychlorinated
biphenyls, or PCBs. The industrial oils, invented in the 1920s, were widely used
in fire extinguishers, hydraulics, and transformers because they resisted flames
and would not conduct electricity. But they were discovered accumulating in
animals in the 1960s, just before an accidental leak into cooking oil in Japan
led to children born with a skin disease, growth problems, and hampered IQs. The
United States banned their production in 1976. Only later did studies resolve
the questions of how they became toxic in the body, and suggest links to cancer
and to learning and memory problems in children.
In the 1980s, after PBDEs were measured in the environment, European scientists
began to turn their attention to this newer class of chemicals. In the 1990s,
studies showed them turning up in women's breast milk; a Swedish study found the
levels had increased 60-fold from 1972 to 1997. PBDEs build up in fatty tissues,
making breast milk a good indicator of both the mother's exposure and the
chemicals in a newborn's diet. Studies since then have found American women's
levels to be much higher than women's levels in Europe and Japan; researchers
suspect that's because two of the PBDE manufacturers are located in the United
States, and because Europe and Japan have been voluntarily phasing out some of
the chemicals for years.
"I often say PBDEs are the poster child for the precautionary principle," said
Tom Webster, a Boston University School of Public Health professor conducting an
analysis of PBDE levels in Massachusetts women. Researchers point to animal
studies that showed learning and behavioral problems in newborn mice fed PBDEs
at particular points of development, stoking fears that PBDEs could cause
learning disabilities and attention deficit disorder in children.
A new analysis compared the "body burden" of chemicals in American women with
the levels that caused problems in animals. About 5 percent of the women studied
had much higher levels of PBDEs than the others, and those women's levels
approached the concentrations of concern in animals, said Thomas A. McDonald, of
the Office of Environmental Health Hazard Assessment in
the California Environmental Protection Agency. "They're pretty close, meaning
the current margin of safety is small for these women."
Scientists are still trying to quantify how much of people's exposure to the
chemicals comes from diet, or whether the chemicals, often found in household
dust, are being inhaled. Researchers suspect some flame retardants leach out of
plastics during the life of
products. Typically, chemical exposure comes from diet, as pollutants in the
atmosphere are taken in by fish, animals, and other wildlife, increasing in
concentration as they move up the food chain to humans.
Some companies, not waiting for regulations, have already stopped using PBDEs.
Dell now uses another flame retardant in its computer equipment, and the
furniture maker Ikea has dropped them for alternative chemicals. But new
chemicals also present unknowns, and there's an obvious cost-benefit analysis in
the debate over a substance intended to promote safety. Untreated polyurethane
foam was partly to blame for the fast-burning Rhode Island nightclub fire that
killed 100 people last year; polyurethane treated with PBDEs burns more slowly.
Because of the difficult tradeoffs, regulators are remaining cautious about one
of the three classes of PBDEs, known as deca, which the industry defends as
benign. Maine legislators intended to ban all three compounds, but after
resistance from the industry they approved a measure that says the state intends
to ban deca in 2008 if a nationally available alternative is found. "They still
gave themselves an escape valve," said the sponsor, Representative Hannah
Pingree. "We were saying you must prove that this chemical is safe, which is, in
a lot of ways, the way you wish you had gone with DDT or mercury or a lot of
other things that
took a lot of years of fighting and proving that there's something wrong with
them."
Stephanie Ebbert can be reached at
ebbert@globe.com
� Copyright 2004 The New York Times Company