Not
that many years ago, many reusable food and beverage containers on the market
worldwide were made from polycarbonate plastic.
Polycarbonate, which is made from bisphenol A (BPA), is an almost ideal
material for these products since its clarity is comparable to glass, making it
easy to see what’s inside, and it’s virtually shatter-proof – an important
attribute for consumer products that could be dropped.
For
years though, BPA has attracted considerable attention from scientists,
environmental activists and the media. Now,
as a result of that attention, few of these products are made from
polycarbonate and a variety of alternative materials are used instead.
What
happened, and was it a good idea to abandon a high performing material with a
safety track record spanning several decades?
With the benefit of 20-20 hindsight, perhaps it’s not surprising that
the safety of the alternative materials is now being called into question.
Could
it be that what seemed like a good idea at the time might have turned into a
regrettable substitution? And what can
we learn from this experience that will help to avoid the same issue for other
materials and products in the future?
A Little History
Polycarbonate
plastic was invented in the 1950s and its use has continued to grow ever
since. Anywhere that a clear, durable
and lightweight material is needed, polycarbonate is a good candidate and you’ll
find it today in countless products that we use every day. From bicycle helmets to components of life
saving medical devices, and eyeglass lenses to safety shields, polycarbonate
makes our lives better and safer.
The
critical ingredient that is necessary to make polycarbonate is bisphenol A
(BPA), which has been the subject of extensive research – and more recently controversy
– about its safety for more than 15 years.
Only trace levels of residual BPA, typically less than 50 parts per
million, remain in polycarbonate plastic, and even smaller trace levels,
typically in the range of 1 part per billion, can migrate into a food or
beverage in contact with polycarbonate under typical conditions of use.
In
spite of repeated and consistent scientific safety assessments by governments, starting
in 2008 some legislatures in U.S. states and later elsewhere began to ban polycarbonate
baby bottles. None actually demonstrated
that polycarbonate is unsafe, and some explicitly stated that their ban was
based on the precautionary principle. As a result, product manufacturers began
moving away from using polycarbonate in baby bottles, sippy cups and other products.
A Little Precaution Goes a Wrong Way
The
general idea behind the precautionary principle is that precautionary measures
should be taken in response to perceived threats to human health or the
environment even if full scientific certainty about the threat is not
available. The principle is sometimes
described in a common sense way as “better safe than sorry.”
From
a scientific perspective, applying the precautionary principle as a solution to
concerns about the safety of BPA seemed inappropriate. Never mind that the actual threat to human
health was not supported by government experts; a precautionary approach doesn’t
provide a mechanism to address the safety of the most likely replacements.
Polycarbonate
had to be replaced with something else, but what? Without knowing what, how is it possible to
know which is safe and which is sorry?
Missing from consideration was the moral from one of Aesop’s Fables,
which is to “look
before you leap.”
In
a commentary published in 2010 by Judy LaKind and Linda Birnbaum, director of
the National Institute of Environmental Health Sciences, in the Journal of Exposure
Science and Environmental Epidemiology, the authors predicted
that there might come a time when the safety of the replacements would be
questioned:
“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. … Our literature search on some of the
replacement … chemicals revealed no exposure information. Years from now, will we be seeing exposure
studies describing certain BPA alternatives as emerging chemicals of concern?”
That
time has now come.
Will We Regret The Substitution?
The
risk of leaping to an alternative chemical before you look is that you might make
a regrettable substitution. Whether the
polycarbonate baby bottle replacements are regrettable may not be entirely
known, but some researchers are starting to ask the question.
Published
very recently is a paper from a group of Belgian researchers titled “Evaluation
of the potential health risks of substances migrating from polycarbonate
replacement baby bottles.” The 24 baby bottles included in the study
were made from five different materials that are now being used as replacements
for polycarbonate bottles. The
researchers evaluated 17 substances that were found in an earlier study
to migrate from one or more of the bottles into a solvent that simulated milk
under real-life use conditions.
The
evaluation was done with a conservative approach that reflected the frequent
lack of adequate data for a thorough evaluation. An exposure range for each substance was
estimated from the level found to migrate under standard test conditions. In the absence of adequate toxicological data
to evaluate safety, assignment of a concern level for each baby bottle was
based on a standard approach known as threshold of toxicological concern, which
is used by government bodies such as the U.S. Food and Drug Administration and
the European Food Safety Authority.
Of
the 24 baby bottles examined, four were designated as “high concern” and another
14 were designated as “concern.” While
these findings reflect potential risk from a conservative assessment rather
than actual harm, they raise the question whether the precautionary principle
was properly applied. In other words, are
the precautionary solutions safe, as intended, or sorry?
It’s Not Just About Baby Bottles
The
case study raises some important questions.
Replacement of polycarbonate baby bottles was largely the result of legislation
driven by consumer demand. Is that the
best way to prioritize our actions? Does
moving from one product to another simply to avoid controversy lead to improved
safety? This might be less of an issue
if alternative materials were being considered only for products that do not
play an important role in protecting human health and safety. Unfortunately those are often the products
where alternatives are most likely to be considered.
For
example, alternatives to polycarbonate are under consideration for critical
components of medical devices. Is this a
good idea when polycarbonate has a multi-decade safety track record and baby
bottles made from the likely alternative material have been designated as a
“concern” in the Belgian study? If your
life depended on it, which material would you choose?
Is BPA-Free Safe or Sorry?
If
the baby bottle saga teaches us anything, it’s that we cannot assume that
BPA-Free means the same thing as safe. This
is not only a scientific question, but a marketplace issue since consumers
regularly see BPA-Free labels and may well factor the information into their
buying decisions. Indeed, BPA-Free
labels are now found on materials like glass, which never contained BPA in the
first place.
Recent
psychology
research examined what consumers understand when they see
BPA-Free labels and how consumer behavior is influenced. The researchers
found that “the BPA-free
label appears to mislead some people into thinking that ‘free’ means ‘safer.’” As the researchers noted:
“This
is not a trivial issue. Consumer
reaction to ‘BPA-free’ and similar labels may in some cases cause people to
make riskier decisions, decisions that feel safer but actually expose them to
agents which may ultimately be more toxic.
‘BPA-free’ labels don’t make it easier for consumers to make reasoned
choices. They lead people to substitute
unconscious assumptions about safety and benefit for reasoned consideration of
what is known or not known about different chemicals and products. And that is truly a regrettable substitution.”
Accordingly,
the researchers note that “such labels are
misleading and cause some people to accept a substitute chemical that they
might otherwise reject.”
Is It Time To Free BPA?
In
light of the demonstrated safety and efficacy of polycarbonate plastic in its
many product applications, and the questions now bubbling to the surface about
alternatives, is it time to revisit the past and Free BPA? Unlike the goat in Aesop’s Fable, we should
look before we leap to avoid regrettable substitutions.
