Introduction
What is BPA?
Coatings Industry's BPA Connection
Why is there so much talk about finding alternative solutions to replace BPA?
EFSA Says BPA is Potentially Unsafe
FDA Says BPA is Safe
CFIA & NAMPA Reaffirm BPA's Safety
What are others saying?
Pro-BPA Opinions Received From SpecialChem Community
Conclusion
References
Introduction
When we began working on the report around BPA-free solutions last year, we knew that we were tapping into a controversial topic. We also knew that extensive research was needed for the same and so we invited our community to share their opinions and preferred solutions with us. There are always two sides to the same coin and while we received several alternate solutions during the past few months, we also received pro BPA feedback. Our aim is to present to you now an unbiased report taking into account both, the industry facts and solutions & opinions shared by the SpecialChem community.
In Part 1 of this report, we are presenting the current regulation status w.r.t. Bisphenol A.
What is BPA?
Though clichéd, beginning with the "what is BPA?" section is important.
Bisphenol A (2,2-bis(4-hydroxyphenyl) propane, CAS No. 80-05-7) is a chemical used primarily as a monomer in the production of polycarbonate plastic (PC), and epoxy resins. It also finds use in polyester, polysulfone and polyacrylate resins, and flame retardants. Polycarbonate (PC) is widely used in food contact materials such as infant feeding bottles, tableware, microwave ovenware, food containers, water bottles, milk and beverage bottles, processing equipment and water pipes. Epoxy resins are used as protective linings for a variety of canned foods and beverages and as a coating on metal lids for glass jars and bottles, including containers used for infant formula. This results in consumer exposure to BPA via the diet.1
As per the recently published report by Transparency Market Research, the revenue generated by the global BPA market was valued at USD 13.1 billion in 2012, which is expected to grow to USD 18.8 billion by 2019, growing at a CAGR of 5.4% from 2013 to 2019. Polycarbonates and epoxy resins accounted for the largest share of the BPA market in terms of both volume and revenue, where ~70% of total volume consumption was accounted for by Polycarbonates.2
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Figure 1: Global Bisphenol-A Polymer Market, 2012 & 2019
(Source: ICIS, Dow Chemicals, PlasticsEurope, Primary Interviews, Transparency Market Research) |
In terms of regional demand, ~50% of total volume consumption in 2012 was accounted for by Asia Pacific. The demand for BPA has been on a rise since 2010 i.e. post revival of global economy with developments in emerging economies [BRIC nations] being considered as one of the main drivers for the steady rise.
Coatings Industry's BPA Connection
Moving on, let us analyze the BPA connection to the coatings industry in greater depth… Canned foods and beverages constitute a major part of the global food supply. Consumers expect canned foods and beverages to maintain their flavor, texture and color and be free of microbes/pathogens. To accomplish this, can interiors are coated with protective resins, one of the most popular choices being epoxy resin.3
However, recently epoxy resins have come under scrutiny because their foundational building block is bisphenol A (BPA). Research indicates that many epoxy-based high performance coatings are made from bisphenol A diglicidyl ether, otherwise known as BADGE. BADGE, in turn, is made from two primary chemicals: bisphenol A (BPA) and epichlorohydrin. Both of these chemicals are suspected of posing significant occupational hazards.4
Theoretically, BPA is consumed entirely in the production of epoxy resins as it is an intermediary chemical and does not show up in the final product. However, there is some indication that some epoxy resin products produced from BPA can be metabolized back into BPA, which can further lead to possible user exposure.
History of Can Coatings4
Cans have been coated since a long time but the technology has progressed from the yesteryear's "tin cans" i.e. iron and steel cans coated with tin to today's cans with polymeric coatings. The idea behind it was the same i.e. the need to increase shelf-life of packaged food and to avoid contamination. Tin cans were found to be susceptible to corrosion leading to contact of food and beverage with the underlying steel/iron leading to contamination. Also, in case of aluminum cans, a thin Al2O3 film layer is needed to prevent corrosion of aluminum. The availability of oxygen within the can determines the possibility of formation of an oxide layer and since that is usually limited in a sealed can, corrosion is inevitable. Additionally, the solubility of this coating increases in conditions like low or high pH and high NaCl concentration.
Thus, an additional organic coating is needed for both steel and aluminum cans.
Several can coating resin types are commercially available, including oleo-resinous compounds (natural oil-based coatings derived from fossil gums) and synthetic resins (acrylic, epoxy, phenolic, polyester and vinyl resins). Resins are usually blended to maximize each attribute according to specific food and beverage properties. Prior to 1965, oleoresins were the only coatings used in cans but they fell out of favor decades ago and had limited uses until recently when the controversy over epoxy resins resulted in increased use.
Comparative View of the Majorly Used Resins in Can Coatings
Table 1 & Figure 2 give a comparative view of the majorly used resins in can coatings. The parameters taken into account for the comparison are:
- Corrosion resistance
- Fabrication
- Application
- Universality
- Consumer acceptance
| Resin Type |
Corrosion resistance (CR) |
Fabrication (F) |
Application (A) |
Universality (U) |
Consumer acceptance (CA) |
| Acrylics - for food contact, acrylics can only be derived from FDA-approved monomers |
Medium [high for non-food contact applications] |
Low |
High |
Low for internal can coatings. (Principally used for exterior can coatings) |
Medium – impart flavor in some cases |
| Epoxies |
High |
Medium – when used alone (unblended), they fail during fabrication of drawn-and-redrawn two-piece food cans. |
High |
High |
High – do not impart flavors, non-yellowing |
| Oleoresins - derived from fusing natural gums and rosins and then blending them with drying oils |
Medium – open micellar structure makes them prone to corrosion |
High |
Low – require long cure times, adhesion to metal is poor |
Low – use is limited to non-aggressive foods. |
Low – do not retain color and tend to impart taste to food. |
| Phenolics |
High |
Low – brittle |
|
Low – poor flexibility |
Medium – impart flavor and odor |
| Polyesters |
Low – ester bond gets attacked in low pH conditions |
- |
High |
Low – poor CR |
Medium – do not impart but absorb flavors (scalping properties) |
| PET Laminates |
Medium – greater thickness than polyester |
High |
High |
Medium – cannot be for welded cans |
High – lower scalping properties than polyester |
| Vinyls |
Low – unblended |
High |
Low – when applied directly over metal substrate. [good, if applied over epoxy base coat] |
Medium – mostly used in cans those are hot-filled for high acid foods |
High – do not impart taste |
Table 1: Comparative view of the majorly used resins in can-coatings4
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Figure 2: Comparative view of the majorly used resins in can-coatings 4
(Sources: Image concept: Joshua Naiman; design: Jeff Aiken Creative Direction LLC) |
Though no single commercially available resin type is suitable for all foods and beverages (acidic, strongly acidic, sulfur-based, etc.), epoxy resins have been seen to rank higher under each parameter in comparison to other resins.
The North American Metal Packaging Alliance (NAMPA) has estimated that 95% of food contact can coatings are epoxy type. Only a very small percentage of epoxy resins do not use BPA as the starting monomer (< 0.1% of epoxy resins are based on bisphenol F and are used only as thermal stabilizers for polyvinyl chloride [PVC] vinyls).
Why is there so much talk about finding alternative solutions to replace BPA?
The potential health effects of Bisphenol-A have been under intense scientific and public scrutiny and debate. Since 2007, there have been more than a dozen comprehensive reviews of BPA by independent government scientists around the world, including in Canada, Europe, Japan, Australia and the United States.
- 2010: Canada was one of the 1st countries to officially declare BPA as a toxic chemical.5 Under the Canada Consumer Product Safety Act, it is illegal to manufacture, import, advertise, or sell polycarbonate baby bottles that contain BPA.6
- 2011: The EU Commission adopted Directive 2011/8/EU in January 2011, which provided for a ban prohibiting the manufacture in the EU of baby bottles containing BPA (March 1, 2011) and a ban on the placing on the market and import into the EU of such products (June 1, 2011).7
- July 2012: Next big announcement came from the US Food and Drug Administration (FDA) in July 2012 stating that it would no longer allow BPA in baby bottles and children's drinking cups. The agency has however, not restricted its use in other consumer products so far.
- December 2012: The 2nd big anti-BPA development of 2012 took place in December when the French Senate imposed a law restricting the use of BPA in food contact materials.
It was decided that by July 2014, the government would have to present to the French National Assembly a report assessing the safety/potential toxicity of alternative materials used to replace BPA and that by Jan 2015, all BPA-based direct food contact materials would no longer be allowed in France. Several sections of the industry were disappointed by this development especially because the law was imposed before the completion of the European Food Safety Authority, EFSA's reassessment of BPA.
Let's review the current status further…
EFSA Says BPA is Potentially Unsafe
EFSA's Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF) had undertaken the reassessment of BPA in March 2012 and on January 17, 2014, launched an online public consultation on its draft assessment of the human health risks posed by exposure to BPA, which ran for two months and fetched 250 responses.
In its draft opinion, EFSA has concluded that exposure to BPA is likely to adversely affect the kidney and liver, as well as causing effects on the mammary glands. The opinion additionally considers the possible effects of BPA on the reproductive, nervous, immune, metabolic and cardiovascular systems, as well as in the development of cancer. While an association between BPA and these other effects is not considered likely at present, EFSA concludes they may be of potential concern for human health and they add to the overall uncertainty about the risks of the substance. EFSA's experts recommend that the tolerable daily intake (TDI) for BPA be lowered from its current level of 50 µg/kg bw/ day (or 0.05 mg/kg/bw/day) to 5 µg/kg bw/day (0.005 mg/kg/bw/day) and be set on a temporary basis.8
EFSA, so far, concludes that BPA poses a low health risk to consumers as exposure to the chemical is well below the temporary TDI. But, it has also said that much of the science underpinning these conclusions is still developing and this draft opinion therefore contains a number of uncertainties. The CEF Panel will complete an assessment of these uncertainties in the final version of the opinion, the publication deadline for which was recently (on April 9, 2014) extended to end of 2014.9This would enable EFSA scientists to dedicate sufficient time on the assessment of the comments received earlier this year and present their final report.
FDA Says BPA is Safe
Close on the heels of the EFSA's report came FDA's report on the safety of BPA.10 The new research was conducted over a year back and the results were recently (in Feb 2014) made public. Two papers have been published by FDA researchers, Mona Churchwell and Barry Delclos who worked on this study with a team of scientists and researchers from FDA's National Center for Toxicological Research, Division of Biomedical Toxicology. The results of the study indicate that metabolites of BPA, and not the compound itself, are found in very low amounts even just a short time after ingestion. Any large measurements of BPA metabolites that can be found in blood or urine are only detected following very large doses of BPA, in amounts that would be impossible to replicate in average consumer's diet. In short, contrary to EFSA, FDA confirms the safety of BPA in consumer products other than baby bottles and sippy cups.
CFIA & NAMPA Reaffirm BPA's Safety
On April 30, 2014, The Canadian Food Inspection Agency (CFIA) released the findings of its latest surveys on canned foods and beverages stating that they found undetectable levels of BPA in 98.5 percent of cans tested, and Health Canada affirmed the trace levels detected in the remaining 1.5 percent of the samples to be safe. CFIA's survey included 403 samples of canned food products collected from retail stores in 11 Canadian cities from April 2011 through March 2012. The results of the survey have found support from the North American Metal Packaging Alliance, Inc. (NAMPA).11
What are others saying?
United States
About half a dozen states have banned BPA in children's products.12 Recently, more bills have been introduced, which go beyond children's products to include ALL food containers:
- BPA Bill Introduced in Wisconsin, US on January 7, 2014: Wisconsin Representative Chris Taylor (D-Madison) has introduced Assembly Bill 607, which requires all food containers manufactured with bisphenol-A (BPA) to be "conspicuously" labeled as containing BPA. 13
- BPA Regulation Proposed in Nebraska, US on February 11, 2014: LB696, introduced by Malcolm Sen. Ken Haar, would prohibit the manufacture, sale or distribution of a reusable food container containing BPA as of January 1, 2015. After the proposed deadline, all food packaging containing BPA would be required to carry the following warning: "This package contains Bisphenol A, a chemical that may harm fetal development, which can leach into the food."14
China
The Ministry of Health announced a ban on BPA-based infant bottles & containers in April 2011. Under the terms of the announcement, the manufacture or import of infant food containers, such as milk bottles, containing BPA was banned as of June 1, 2011, and the sale of such products in China was restricted starting September 1, 2011.15
Japan
National Institute of Advanced Industrial Science and Technology, AIST's Bisphenol-A Risk Assessment Document published in 2007 concluded that the risks posed by BPA were below the levels of concern, thereby making it unnecessary to prohibit or restrict the use of BPA at the time.16
Also in 1998, can manufacturers were asked to reduce migration level to almost 0 by canned drink manufacturers. Two approaches were employed to reduce the migration of BPA. One was to change the inner surface inactivation of cans from the Epoxy coating to the PET film lamination and the other was to use Epoxy coating from which a small amount of BPA migrates.
Australia and New Zealand
A voluntary phase out of BPA-based baby bottles was initiated in 2010.17
In addition, the Australian Competition & Consumer Commission (ACCC) in association with the other relevant Australian government regulatory agencies like Food Standards Australia New Zealand (FSANZ) and more, are involved in the assessment and monitoring of BPA. They remain convinced that the weight of evidence, obtained from an extensive range of safety studies, indicates that BPA is safe for the whole population at the very low levels of current exposure. If future evidence shows any risks to human health and safety, the ACCC has the power to ban products or develop mandatory standards with compulsory safety requirements that products must meet to minimize risks.18
South Africa
The Minister of Health has banned the manufacturing, importation, exportation and sale of polycarbonate (PC) infant feeding bottles containing Bisphenol A, as published in the Government Gazette on October 21, 2011.19
Pro-BPA Opinions Received From SpecialChem Community
Without the intention of passing a judgment on the safety of BPA, SpecialChem contacted its community directly to get them to share with us the alternatives. This was done to really know if there were enough proven solutions to face a situation wherein some anti-BPA regulations get passed.
The community responded in good numbers to this hot topic and while we received a considerable number of alternative solutions, we also received pro-BPA opinions from some of them. Few examples have been quoted below.
Steven G. Hentges, Ph.D., Head of the American Chemistry Council-affiliated Polycarbonate/BPA Global Group, wrote to us asking an important question: why replace BPA at all?20
His arguments are broadly based on performance and safety of BPA:
- BPA Has Been Used for Decades Because It Does Perform Very Well: For both polycarbonate plastic, being used in several applications for decades and epoxy resins, being used for over 50 years, it is not a simple matter to find a material that can match the attributes and performance of these materials.
- Government Agencies Worldwide Support the Safety of BPA: The positive views expressed by FDA in 2013 are hardly unique and have been expressed recently by many regulatory agencies that have each independently evaluated the science on BPA. Other recent examples of government reviews include:
- Hong Kong Centre for Food Safety (March 2013)
- Health Canada (September 2012)
- Food Standards Australia New Zealand (April 2012)
- European Food Safety Authority (January 2014)
- Swiss Federal Office of Public Health (December 2011)
- Japanese National Institute of Advanced Industrial Science and Technology (July 2011)
- German Federal Institute for Risk Assessment (May 2011)
(More available on: http://www.factsaboutbpa.org/benefits-applications/why-bpa)
He further adds, "It is not likely that any alternative has been so thoroughly tested or so comprehensively and frequently reviewed by government agencies as BPA."
Ray Calladine, Sales & Marketing Director at Nama Chemicals LLC wrote to us saying, "I have to say that the pressure to find BPA-alternative is not really apparent in the market - only from people who have not really studied the facts. We will see less safe solutions in the market or worse, as with REACH. No one bothers with real R&D in Europe any longer and we in the industry have to try and get realism into the politicians before it is too late. If this trend continues, Europe will be 3rd world within 20 years as everyone overtakes us on technology."
Similar views were shared by some more members, who also challenged the very need to replace BPA. Some claimed it to be more of a "political hunt", while some others said that it was more to do with "sociology than chemistry". Technical arguments included the fact that no residual BPA should ideally remain once the resin has got cured (epoxy) or post completion of polymerization (polycarbonate) and that the manufacturers should be able to bring down residual BPA (if any) to acceptable levels.
Having received a mixed bag of responses, it was clear to us that this debate was a never-ending one. Only time (and further regulations) would tell what solutions the industry would eventually adopt.
Conclusion
In this part of the report, we have discussed the coating industry's connection to Bisphenol A (BPA), the history of can coatings and provided a comparative view of all the available resin solutions for the same. Further, we have presented the regulatory status w.r.t. BPA.
In the next part of the report, we will feature the alternative solutions shared by the SpecialChem Community Members. Watch this space for more!
References
- http://www.who.int/foodsafety/publications/fs_management/No_05_Bisphenol_A_Nov09_en.pdf
- http://www.transparencymarketresearch.com/bisphenol-a-market.html
- LaKind, J.S. (XXXX) ‘Can coatings for foods and beverages: issues and options', Int. J. Technology, Policy and Management, Vol. X, No. Y, pp.xxx–xxx
- FACT SHEET: BISPHENOL A IN HIGH PERFORMANCE PAINT COATINGS- July 2009, Written and produced by Healthy Building Network. Production funded by the Global Health and Safety Initiative with the support of Health Care Without Harm.
- http://www.nytimes.com/2010/10/14/world/americas/14bpa.html?_r=0
- http://healthycanadians.gc.ca/environment-environnement/home-maison/bisphenol_a-eng.php
- http://europa.eu/rapid/press-release_IP-11-664_en.htm
- http://www.efsa.europa.eu/en/press/news/140117.htm
- http://www.efsa.europa.eu/en/press/news/140409a.htm
- http://www.eurofoodlaw.com/country-reports/americas/fda-researchers-further-support-safety-of-bpa-96975.htm
- http://www.metal-pack.org/docs/pdf/NAMPA%20Press%20Release%204.30.pdf
- http://www.ncsl.org/research/environment-and-natural-resources/policy-update-on-state-restrictions-on-bisphenol-a.aspx
- https://docs.legis.wisconsin.gov/2013/related/proposals/ab607.pdf
- http://update.legislature.ne.gov/?p=14597
- http://www.cecc.gov/publications/commission-analysis/ministry-of-health-issues-draft-ban-on-the-use-of-bpa-in-infant
- https://unit.aist.go.jp/riss/crm/mainmenu/BPA_Summary_English.pdf
- http://www.foodproductiondaily.com/Packaging/Australia-introduces-voluntary-bisphenol-A-phase-out
- https://www.productsafety.gov.au/content/index.phtml/itemId/971446#h2_44
- http://www.plasticsinfo.co.za/default.asp?CPH_ID=1271
- http://www.factsaboutbpa.org/benefits-applications/why-bpa
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