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Is BPS a Safe Alternative to BPA?

Rapid Response Question:

1) What is the latest understanding of the toxicology of BPS (bisphenol S)?

2) Can BPS be considered environmentally superior to BPA (bisphenol A)?

3) Should recycling paper mills be concerned about discharging BPS into the water supply?

4) Do you know to what extent BPS has replaced BPA in the receipt market?

Request by: Paul de Block, Bureau of Planning & Sustainability, City of Portland

UPDATE (5/8/15): Since this report was published, in May 2012, new information has become available.

Some companies are taking actions to develop safer receipts that avoid the potential – even if still uncertain – risks associated with BPA and BPS. In October, 2014, PCC Natural Markets switched to phenol-free receipt paper that uses vitamin C as an alternative. The paper, developed by Appvion, Inc., contains no dyes, and no BPA or BPS.
In January, 2014, EPA released a final alternatives assessment for bisphenol A (BPA) in thermal paper. At the time of the release of this EPA report, the authors and stakeholders had found no clear alternatives for BPA in thermal paper. The report does, however, discuss considerations for selecting thermal paper developers. Because the report includes extensive hazard assessment information, it can also be used inform further analyses on preferred alternative chemicals, such as risk assessments or life-cycle assessments.

Key Findings

A US Environmental Protection Agency (EPA) Design for the Environment (DfE) partnership program has summarized preliminary data on the chemical hazards of BPA, BPS and other alternative chemicals for use in thermal paper. No clear “safe” alternative has emerged from the EPA DfE work to date.
PPRC reviewed the preliminary hazard evaluations for BPS versus BPA. The picture is complex as there are many hazard criteria, with some criteria worse for BPS with others worse for BPA. The EPA analysis suggests that BPS is less potent than BPA in some tests of endocrine activity.
Regarding discharges to the aquatic environment, BPS has lower aquatic toxicity than BPA, but is more persistent in the environment. PPRC recommends a more detailed follow-up analysis of the environmental impact of BPS releases from papermaking or recycling facilities.
PPRC did not find any information on the relative amounts of BPS- versus BPA-based thermal paper in the US market. In 2010, Appleton Papers described a plan to incorporate “easy-to-see” red threads in their BPS-containing thermal paper to help consumers identify their product. This may offer consumers or other parties an opportunity to assess the overall penetration of Appleton BPS papers in the overall market.
Recent biomonitoring data suggest that consumers are being exposed to BPS. While mainly used in thermal paper, BPS was found in a variety of other paper products, perhaps introduced inadvertently in the papermaking process or via recycled materials.
No information was found to quantify market penetration of BPS-containing paper, however, BPS has been used domestically by Appleton since 2006.

Background

In 2009 and 2010, following years of controversy on the use of BPA in polycarbonate bottle products, a number of publications identified possible concerns over the use of bisphenol A (BPA) in thermal paper for point-of-sale (POS) receipts. PPRC’s summary of the issue was published as a Rapid Response in 2010 (read it here). In 2010, Appleton Papers, the largest US manufacturer of thermal paper announced that they had changed their process to eliminate BPA from their products beginning in 2006. Later, Appleton reported that BPA had been replaced by 4-hydroxyphenyl sulfone, also known as bisphenol S (BPS). This same fact sheet reports Appleton’s finding that BPS is a better option for thermal paper than BPA:

“We have reviewed the scientific literature about the toxicology of thermal developers and have concluded that BPS is a better choice than BPA for overall product safety. Outside expert opinion, supports our conclusions.”

To PPRC’s knowledge, no additional data on BPS chemical hazards have been released by Appleton.

In 2010, the US Environmental Protection Agency convened a broad range of stakeholders to consider chemical alternatives to BPA for thermal paper manufacture under the Design for the Environment (DfE) partnership program. Appleton, a variety of other thermal paper manufacturers, NGOs and others have been participating in the DfE stakeholder partnership. This voluntary effort has generated significant data on possible alternatives to BPA, including BPS. As the data are in draft form, results should be viewed with caution and may change prior to the formal publication of results expected later this year (2012).

DfE Hazard Evaluations for BPA Alternatives in Thermal Paper

The DfE partnership identified 19 chemicals that might be useful alternatives to BPA in thermal paper. US EPA staff completed draft hazard evaluations for BPA and these alternatives in 2011. The hazard evaluations summarize chemical, toxicological and environmental information and include a comprehensive list of a dozen or so hazard criteria. Among these are carcinogenicity, reproductive toxicity, endocrine activity, persistence, aquatic toxicity, etc. Each criterion is evaluated from existing data or models of chemical properties and assigned a value of High, Moderate or Low (and for some endpoints Very High or Very Low). For a criterion such as reproductive toxicity, a value of High indicates high toxicity relative to US EPA established ranges (see the DfE alternatives assessment criteria available here).

Given the large number of criteria, the complexity of interpretation, and the preliminary nature of the hazard data, we present only a brief subset of the information for BPS and BPA. BPS and BPA are compared against each other as relatively better (+), worse (−) or neutral (0) for the subset of criteria reviewed (ratings assigned by PPRC based on US EPA hazard values), Table 1. For example, if BPA exhibits a High value for a criterion and BPS has a Moderate value for the same criterion, then BPA will be listed here with a “−“, i.e., worse, and BPS with a “+”, i.e., better.

The DfE program has not ranked alternatives as overall better or worse and the data shown in Table 1 for BPA and BPS demonstrate the challenge of ranking chemicals based on hazard traits. BPA and BPS seesaw across the various endpoints showing no consistently higher or lower level of hazard. It’s also important to consider differences in the persistence of these compounds in the environment. For example, BPS has better (lower) acute aquatic toxicity, and in that sense is “safer” for aquatic life, however, BPS has higher persistence in the environment (i.e., it remains in the environment for a longer time) increasing the chances that aquatic life will be exposed to BPS compared with BPA.

Much of the concern about BPA surrounds its well-established endocrine activity and the possible harm from exposure to vulnerable populations during critical periods of development. The DfE assessment reports that BPS behaves as a weak estrogen and provides additional data suggesting that BPS has lower potency when compared with BPA in similar experiments on endocrine activity. These results may change over time as data is further developed by EPA. Authoritative, up-to-date results can be provided by Dr. Cal Baier-Anderson at EPA: baier-anderson.caroline@epa.gov.

Utilization of BPS versus BPA in Thermal Paper and Exposure Potential

In 2010, an Appleton factsheet announced a plan to incorporate fine red fibers (similar to currency paper) to help consumers distinguish their BPS-containing thermal paper from other papers. If this plan was carried through, it may offer consumers an opportunity to identify BPS-containing products from Appleton. No other information on market penetration of BPS-papers was available for the US. Anecdotal reports suggest that BPS has also been used in Japan as a BPA-replacement.

Two recent publications (see references below) have examined the occurrence of and exposure to BPS in paper products. Consistent with earlier research on BPA, researchers found that BPS has found its way into newspaper, food contact papers and paper towels, among other products probably via the recycling process. The spread to other paper products is likely exacerbated by BPS’s higher persistence. Like BPA, BPS has been identified in urine samples from US subjects. A brief summary of this research can be found in a publicly accessible C&E News article or in the original research by Liao et al. (see References below).

Summary

There is no simple way to describe the overall hazard of BPS relative to BPA. The DfE preliminary data confirm that BPS appears to exhibit somewhat less potent endocrine activity versus BPA, however chemicals pose potential hazards beyond endocrine activity. In the comprehensive list of hazard criteria reviewed by DfE, the picture is complex, with some hazards higher for BPS with others higher for BPA. No clear “safe” alternative has emerged from the EPA DfE work (in progress).

Recent research (Spring 2012) shows that consumers are being exposed to BPS. As with BPA, BPS is moving beyond thermal paper into a wider range of paper products likely via the paper recycling process.

References

Appleton’s fact sheet on their replacement of BPA with BPS: http://www.appletonideas.com/Appleton/jsps/pdf/thermal/BPA_Statement.pdf
Appleton’s fact sheet on red fibers in BPS-containing papers: http://www.appletonideas.com/pdf/Appleton%20Red%20Fibers%20Receipt%20News%20Release%2011-08-10.pdf
EPA’s BPA Alternatives in Thermal Paper Partnership” http://www.epa.gov/dfe/pubs/projects/bpa/index.htm
EPA’s alternatives assessment methodology: http://www.epa.gov/dfe/alternative_assessments.html
EPA’s assessment criteria for hazard evaluation: http://www.epa.gov/dfe/alternative_assessments.html
C&E News article on recent publications regarding BPS in thermal paper: http://cen.acs.org/articles/90/web/2012/05/BPA-Replacement-Permeates-Paper-Products.html
Liao et al., Bisphenol S, a New Bisphenol Analogue, in Paper Products and Currency Bills and Its Association with Bisphenol A Residues, ES&T 2012, http://pubs.acs.org/doi/abs/10.1021/es300876n
Liao et al., Bisphenol S in Urine from the United States and Seven Asian Countries: Occurrence and Human Exposures, ES&T 2012, http://pubs.acs.org/doi/abs/10.1021/es301334j
Bisphenol A Alternatives in Thermal Paper: Final Report. 2014. http://www2.epa.gov/sites/production/files/2014-05/documents/bpa_final.pdf