There’s
an emerging trend, of late, in the seemingly endless saga of the chemical
bisphenol A (BPA),
which is most commonly used to make polycarbonate plastic and epoxy resins.  Although the BPA saga has not yet become
completely passé, much of the attention that had been given to BPA is now
focused on alternatives to BPA.  Indeed, it
seems that BPA-Free is becoming the new BPA.

For
what seemed an eternity, BPA had been at the center of a perfect storm
comprised of scientists, regulators, legislators, environmental activists and
the media.  Their collective fascination
with BPA struck many as bordering on obsession.

Over
the last decade, thousands of studies on BPA have been published by scientists
around the world and, in response to the flood of scientific data, regulatory
agencies conducted numerous safety/risk assessments.  Attracted to the controversy and spurred on
by environmental activists, legislators proposed to ban products containing
BPA.  On all fronts, media coverage has
both reported on and promoted the controversy.

Image credit: BevNet

The
scientific process may not be speedy, but we must trust that science will
eventually cut through the controversy and resolve uncertainties about the
safety of BPA.  Thanks in large part to a
remarkable research program designed and conducted over the last several years
by the U.S.
Food and Drug Administration (FDA) in conjunction
with the U.S. National Toxicology Program (NTP), that’s exactly what is
happening.  With extensive
results from that program now available, FDA recently answered
the question “Is BPA safe?”
with the most straightforward answer possible – “Yes.”

In
spite of continued safety assurances from government agencies, BPA is no longer
used in a few markets.  For example, it’s
well known that baby bottles and most sports bottles are no longer made from
polycarbonate plastic.  But with
controversy about the safety of BPA now in decline, the BPA-Free alternatives
are coming under attack from some of the same players who previously had
targeted BPA. 

This
shouldn’t really be a surprise and, in fact, it was predicted 4 years ago in a
prescient commentary published by Judy LaKind and Linda Birnbaum in the Journal of Exposure
Science and Environmental Epidemiology:

“There are too many
examples of chemicals taken off the market only to be replaced with chemicals
that, in time, come to be considered ‘of concern.’  We may be at such a juncture with replacement
chemicals for bisphenol A (BPA) and PFOS.  BPA, used mainly in the production of
polycarbonates, has been measured in >90% of the general US population,
prompting calls for bans, which have been enacted for certain uses in some
parts of the United States and proposed in other countries. 

This has in turn resulted in a demand for
alternatives to polycarbonate bottles, including glass and metal bottles and
those made from a copolyester (C&EN
News, 2009), which is marketed to both adults and children.  Our literature search on some of the
replacement copolyester chemicals revealed no exposure information.  Years from now, will we be seeing exposure
studies describing certain BPA alternatives as emerging chemicals of concern?”

With
BPA so well-studied over so many years, it should be no surprise that BPA-Free
alternatives are not nearly as well studied. 
That’s doesn’t by itself mean anything. 
But the difference in available data for BPA and BPA-Free alternatives
is now becoming very apparent and is attracting scientists like bees to
honey. 

Some
researchers are studying plastics, including the copolyester mentioned above
that is an alternative to polycarbonate, and report that “[e]strogenic chemicals often leach from BPA-free plastic
products that are replacements for BPA-containing polycarbonate products.”  The
researchers also appropriately note that their data “can only describe the existence of a possible hazard for consumption of
chemicals with EA [estrogenic activity]
leaching from plastic products, not what risk that consumption might have to
human health,” which suggests that more research may follow.

Other researchers are studying BPA analogues
(i.e., chemicals with similar structures that might be used in place of BPA to
make plastics or resins), in particular bisphenol S (BPS), which is currently used
as an alternative to BPA in thermal receipt paper.  As predicted 4 years ago, recent exposure
studies report human exposure to BPS and the presence of BPA analogues in various environmental compartments
including food, paper
products, indoor
dust, and freshwater
sediment.

With limited data available, studies relevant to
potential human and environmental health effects from BPS and other analogues are
also starting to appear.  Very
reminiscent of many earlier studies on BPA, some researchers are announcing
their findings both in the form of a scientific
paper and a press release to attract further attention.

But just like the early days
with BPA, these new research results are difficult to interpret with respect to
the safety of the BPA-Free alternatives as they are being used.  As is often stated at the end of these
papers, more research is needed and, almost certainly, more research will be
done. 

Beyond the few studies cited here, the number of
studies focused on alternatives to BPA is clearly on an upward trend.  As stated by NTP, “[t]here is a considerable amount of data available on BPA toxicities;
however, very little is known about the potential replacement chemicals.”  In particular, “there is insufficient in vivo toxicological data to adequately
characterize the possible human health effects of BPS” and, for that
reason, NTP is currently considering a comprehensive research concept on BPS.

With
new research results and controversy expanding to BPA-Free alternatives, it’s
not just scientists who are taking an interest. 
Government agencies have also taken an interest, initially focused on
alternatives to BPA in thermal receipt paper. 
Already assessments have been conducted by the U.S.
Environmental Protection Agency (EPA), the Danish
Ministry of the Environment, and the State
of Minnesota. 
As concluded by EPA, with similar conclusions from the others, “[n]o clearly safer alternatives to BPA were
identified in this report…”.  Further
such analyses are anticipated.

As
scientists and government agencies turn their attention to BPA-Free
alternatives, environmental activists and the media will not be far
behind.  With headlines like “The Scary New Evidence on BPA-Free Plastics” and “BPA-Free Plastic Containers May Be Just as Hazardous,” the media barrage may be just
beginning.  For a while, it may have
seemed that BPA-Free product labels would be a good selling point, but now the
labels may become a target. 

Labels proclaiming that a product is free of something are not unique to
BPA.  In general, though, such labels are
not very informative.  The right question
to ask is not what a product is free of, but what is the product made from and
what is known about its safety?  Further
discussion on this topic may be the focus of a future article.