AbstractBackground: The majority of receipts printed on thermal paper contain high levels of

Bisphenol A (BPA), a xenoestrogen that is a suspected developmental and reproductive

toxicant (NTP 2008). BPA is associated in animal tests and/or human studies with the

disruption of thyroid function, neurological function, some cancers (including breast and

prostate cancer), and infertility (Vandenberg 2007). Thermal receipts pose unique concern

because the levels of BPA are 250-1000 times the amount found in plastic (EWG, 2010), and

secondly, the BPA in thermal receipts is not bound to a polymer, making it easily transferred

to one’s skin where it can then be dermally absorbed (Zalko et al. 2010).

Objectives: In order to investigate the potential relationship between frequent handling of

thermal receipts and increased exposure to BPA, we analyzed data from the National Health

and Nutrition Examination Survey (NHANES). Secondly, we analyzed the life cycle of thermal

receipts. Finally, we ranked alternative receipt technologies according to Green Chemistry

principles.

Results: A look at the life cycle of thermal receipts reveals potentials for resource depletion

and environmental pollution and contamination with chemicals besides BPA. Thermal receipts

have the potential to affect human and environmental health through chemical pollution and

contamination during the production, recycling and disposal stages. Alternatives to the current

direct thermal printing technology include thermal transfer technology, possible photochromic

UV technology, and electronic receipts.

Conclusion: We recommend taking a precautionary approach and switching the current

practice of using thermal paper for receipts to an electronic receipt system.

BPA: what level is safe?

Both Japan and the United States (under the EPA) have set cutoff

values for protection against reproductive harm:

• Japan established safe intake level of 0.5 mg/kg/day

• U.S. EPA established a range of 0.05-0.5 mg/kg/day

Yet, a literature review performed by Vandenberg et al. (2007)

analyzed 150 published studies regarding BPA toxicity and

demonstrated that 40 of these studies demonstrate developmental

and reproductive harm in levels less than the 0.05 mg/kg/day dose

(Vandenberg et al., 2007).

Conclusion: It appears that the current safety level of BPA is not accurately

reflected in the regulatory standards set in both Japan and the U.S. Given

the research findings where low-dose exposure is associated with

developmental and reproductive harm, examining the current set cutoff level

for protection is recommended.

Pathways of BPA exposure

Ingestion

Food and drink has been thought to account for 80-90% of aggregate BPA exposure.

This percentage is now under question: A study analyzed urinary concentration of BPA in fasting individuals. No significant decrease in BPA urinary excretion was demonstrated. Absence of a decline in BPA excretion over the fasting time period suggests that there may be other significant sources of exposure (Stahlhut et al., 2009).

Dermal absorption

Until recently, dermal absorption was not thought to significantly contribute to one’s aggregate exposure.

The first study analyzing BPA absorption using viable human skin found that 46% of dermally-applied BPA is absorbed (Zalko et al., 2010).

Analysis of NHANES data

Individuals who were occupationally exposed are

more likely to have BPA detected in their urine.

915 individuals in the 2003-2004 cohort had data on occupational status, BPA

excretion levels, and creatinine levels (used to adjust for urinary concentration).

These individuals were grouped into exposed (sales workers, retail and personal

services, and waitstaff) and unexposed (all other workers).

Individuals who were occupationally exposed

have higher concentrations of BPA in their urine.

Potential source of BPA dermal exposure:

thermal receipts

About Paper

Thermal Paper

www.torraspapel.com 3

Fig r.

. 1: Mode of operation and composition of thermal pape

As already indicated above, heat is applied to the paper by means of a thermal header, the basic working of which is shown in figure 2. As can be seen, the thermal paper is pulled along by a roller, and on passing through the thermal header the thermal coating will melt, thus reproducing the image that we wish to print (it should be noted that total melting of the coating does not occur: melting only occurs in the case of the components directly involved in the formation of the image). The melted products are partially absorbed by the under-coating, so that the excess melted material does not stick to the heat-generating header.

Fig. 2: Application of heat by means of the thermal header.

1.1. The coating mix

The thermal coating is obtained from a mixture of materials (or coating mix) made up of a series of chemical products including a colouring, a sensitizing agent, a colour enhancer, and many other components (we shall see later how the coating is applied to the base paper.) The chemical reaction produced between some of these products is what induces the printing process on the base paper when the heat generated by the thermal header is applied.

In the case of thermal paper, all the products that induce printing are already present in the coating mix itself. This is a fundamental difference with the mixture used for self-

About Paper

Thermal Paper

www.torraspapel.com 3

Fig r.

. 1: Mode of operation and composition of thermal pape

As already indicated above, heat is applied to the paper by means of a thermal header, the basic working of which is shown in figure 2. As can be seen, the thermal paper is pulled along by a roller, and on passing through the thermal header the thermal coating will melt, thus reproducing the image that we wish to print (it should be noted that total melting of the coating does not occur: melting only occurs in the case of the components directly involved in the formation of the image). The melted products are partially absorbed by the under-coating, so that the excess melted material does not stick to the heat-generating header.

Fig. 2: Application of heat by means of the thermal header.

1.1. The coating mix

The thermal coating is obtained from a mixture of materials (or coating mix) made up of a series of chemical products including a colouring, a sensitizing agent, a colour enhancer, and many other components (we shall see later how the coating is applied to the base paper.) The chemical reaction produced between some of these products is what induces the printing process on the base paper when the heat generated by the thermal header is applied.

In the case of thermal paper, all the products that induce printing are already present in the coating mix itself. This is a fundamental difference with the mixture used for self-

Direct Thermal Technology•Thermal paper, containing the

color former and color

developer is fed through a

platen roller.

•Image is formed when heat

applied by the thermal head

activates the chemical reaction

between the former and

developer.

• Additives enhance the

image quality and

printability of

thermal receipts.

Torraspapel, 2008 About Thermal Paper, www.toraspapel.com

BPA as Color Developer

BPA donates protons that attack the lactone ring of the color former.

BPA is the common choice for color developer because of:•high color contrast

•stable image

•low acidity

•low cost

•easy availability

spirolactone dye

CH3CH3

OH OH

Bisphenol A

Additives in Thermal Receipts• Binders: Adheres coating to the base paper. Cellulose, polyvinyl

alcohols, long chain aliphatic compounds.

• Sensitizers: lower the melting temperature. Fatty acids or aromatic compounds with melting points near 100C.

• Stabilizers: move equilibrium point towards colored species. Hindered phenol derivatives.

Protect image against plasticizers and oil. Aromatic carboxylic acid

metal salts.

Protect image against UV. Benzophenone and triazole type compounds.

• Lubricants: prevent the coating from sticking to the thermal head. Metallic salts of fatty acids.

• Fillers: absorb melted components. White pigments and inorganic compounds .

Advantages of Direct Thermal

Technology

- No consumables at point of sale besides paper

- Low cost

- Reliable

- Compact & portable

- Quick printing speed

- Simple to use & maintain

- High resolution

- Quiet operation

depletion of forests

from unsustainable

forest management

formation of chlorinated organic compounds from

using bleaching agents containing chlorine

pollution of air, water, and soil from chemicals used in thermal paper

manufacturing

occupational exposure

to chemicals during

chemical and thermal

paper manufacturingLandfilling of solid waste:

groundwater contamination and release of methane

Incineration of solid waste: release of air pollutants

contamination of air, water, and soil with

chemicals from thermal paper

recycling

chemical

contamination of

recycled paper

products and

corrugated media

Potential Life Cycle

Impacts

occupational exposure

to BPA at the point of

sale

Alternative 1: Improving Current Direct

Thermal Technology (DTT)

• Maximize recycled fiber content and use wood fiber from environmentally and socially responsible sources in base paper. Use renewable feed stocks (GC 7)

• Use electricity from renewable sources during thermal paper manufacturing. (GC 7)

• Substitute oxygen-based compounds for chlorine compounds in pulping and bleaching processes, and work towards totally effluent free mills. Prevent pollution (GC 1)

• Use intrinsically thermally sensitive compound, cutting the need of auxiliary reagents. Increase atom economy (GC 2)

• Replace the „necessary‟ non biodegradable auxiliary reagents with biodegradable reagents. Design for degradability (GC 10)

• Use closed systems to minimize worker exposure.

Alternative 2:Thermal Transfer Technology(TTT)

• Heat is transferred

from thermal head to

the ribbon, which is a

polyester coated with

wax or resin ink.

• The heat melts the ink,

which diffuses, is

absorbed and becomes

part of media.

Advantages of TTT

•extremely durable images

•high printing speed

•high resolution images

wax/resin, carbon black

silicon

polyester

Direct Thermal and Thermal Transfer Book, www.upmraflatac.com

Alternative 3: Photochromic paper using UV Light

Advantages of Photochromic technology compared to current DTT

• faster reaction; faster printing

• longer receipt life, thermally irreversible reaction

Colorless ColoredThis reaction is reversible but the reversibility can be controlled by changing the

derivitization, temperature and solvents.

The “Photochromic Paper” has light sensitive compounds

which change color on exposure to UV Lamp.

313 nm

527 nm

Alternative 4: Electronic Receipts• Digital: Customers create online account with a company ( e.g.

allElectronic). All receipts automatically sent to their account by linking the credit card number or phone number used at purchase.

• Web Based Receipts: Paperless receipts sent to the customer‟s email address, given at time of purchase to cashier ( e.g. TransactionTree).

• Near Field Communication Technology: Customers can swipe credit cards as payment directly with Iphone6 or Android, using Square ( plastic cube fitting into the earplug holes). On swiping the card, reader converts the data from magnetic strip into audio signal and passes it onto the phone software.

Advantages:

• Ease of tracking & storing receipts

• Saving trees, oil, emissions

• No new gadgets needed,

adding application to existing

electronic technology.

Mathew Honan, 2010, Iphone Credit Card Reader Lets You Accept Plastic Anywhere, http://www.wired.com/reviews/2010/02/pr_square_iphone

Green Chemistry Ranking of TechnologiesGreen Chemistry

Metrics

Direct Thermal

Technology

Photochromic

UV Technology

Thermal Transfer

Technology

Electronic

Receipts

Atom economy (GC 2) .62 1.0 0.14 0.0

# Chemicals main

reaction ( GC 5)1.0 0.5 0.5 0.0

1Toxicity (GC 3) 1.0 0.13 0.13 0.0

2Carcinogenicity

(GC4,5)1.0 0.33 0.67 0.0

3Estrogenicity ( GC 4,5) 1.0 0.0 0.0 0.0

4Biodegradability

(GC10)1.0 0.25 0.25 0.0

Chemical waste

(user level) (GC 1)1.0 1.0 0.5 0.0

Energy cosumption(

user level) (GC 6)0.5 1.0 0.75 0.1

Average 0.93 0.60 0.42 0.01

Ranking 4 3 2 1* Lower number means that the technology follows the green chemistry principle1 Toxic Release Inventory List

2 OSHA Carcinogens List

3 Terasaki, Shiraishi,Makino, 2007, Occurrence and estrogenicity of phenolics in paper recycling process water: Pollutants originating from thermal paper in

waste paper, Environmental Toxicology and Chemistry

4 http://www.synthesia.eu/external-data/bl/383_benzyl%20 naphthyl%20ether_en.pdf

Personal Protective Actions

We recommend changing the current DTT. In the mean

time, the following actions should be taken to minimize

BPA exposure from thermal receipts.

•Decline receipts whenever possible.

•Do not touch receipts with wet or greasy hands.

•Store receipts separately in an envelope and away

from children.

•Do not crumple receipts.

•Do not recycle thermal receipts.

•Wash hands with cold water after handling receipts.

Do not use alcohol-based hand cleansers.

ConclusionBPA is a suspected human reproductive and developmental toxicant that causes

biological harm in low doses that are environmentally relevant. Individuals

working in occupations with high levels of exposure to thermal receipts have

higher levels of BPA in their urine compared to individuals who do not have high

occupational exposure to thermal receipts. Failure to account for non-food

exposure to BPA may underestimate actual BPA exposure, particularly for highly

exposed occupations. Besides exposing workers and consumers to BPA,

thermal receipts use chemicals that have downstream effects on human and

environmental health that result from ineffective waste management. Most

chemicals used in thermal receipts lack safety data. Under TSCA, chemicals in

production are not required to be proven safe, so BPA-free receipts may contain

other compounds that pose hazard. Due to the uncertainty regarding safe level

limits of BPA exposure and the safety of other chemicals, we recommend taking

a precautionary approach and using safer receipt technologies. After assessing

the current direct thermal technology and the alternate thermal transfer,

photochromic UV, and electronic receipt technology, according to Green

Chemistry Principles, we identified electronic receipts as following the most

number of GC principles.

References

CDC. Centers for Disease control and Prevention. National Center for Health Statistics (NCHC). National Health and Nutrition Examination Survey Data. Hyattsville, MD: U.S. Department of Health and Human Services, 2010 http://www.cdc.gov/nchs/nhanes/nhanes2003-2004/nhanes03_04.htm.

EWG. Environmental Working Group. Synthetic estrogen BPA coats cash register receipts. 2010. http://www.ewg.org/bpa-in-store-receipts

NTP. National Toxicology Program. 2008. U.S. Department of Health and Human Services. Center for evaluation of risks to human reproduction . NTP brief on Bisphenol A [CAS No. 80-05-07].

Stahlhut RW, Welshons WV, Swan SH. 2009. Bisphenol A data in NHANES suggest longer than expected half-life, substantial nonfood exposure, or both. Environ Health Perspect 117(5): 784-9.

Vandenberg LN, Hauser R, Marcus M, Oldea N, and WV Welshons. 2007. Human exposure to bisphenol A (BPA). Reprod Toxicol 24(2): 139-77.

Zalko D, Jacques C, Duplan H, Bruel S, Perdu E. 2011. Viable skin efficiently absorbs and metabolizes bisphenol A. Chemosphere 82(3): 424-430.

Diamond, Arthur S. and Weiss, David S., [ed.]. Handbook of Imaging Materials. 2nd Edition. New York : Marcel Dekker, 2002. p. 443.

Muthyala, Ramaiah, [ed.]. Chemistry and applications of leuco dyes. New York : Plenum Press, 1997. p. 200.

European Commission Joint Research Centre and Institute for Health and Consumer Protection. European Union Risk Assessment Report: bisphenol A. 2003.

Gehring, M., et al. Bisphenol A Contamination of Wastepaper, Cellulose and Recycled Paper Products. [ed.] C. A. Brebbia, et al. Waste Management and the Environment II. WIT Transactions on Ecology and the Environment. Southampton : s.n., 2004, Vol. 78, pp. 294-300.

Michaelangelo D. Tabone, James J. Cregg, Eric Beckman, Amy Landis, 2010. Sustainability Metrics: Life Cycle Assessment and Green Design Polymers, Envrron Sci. Technol

Torraspapel, 2008 About Thermal Paper, www.toraspapel.com

Michinori Takeshita, Takehiko Yamato,2001, Synthesis and photochromic properties of 1,2, dicyano[2,n] metacyclophan, Science Direct

Mathew Honan, 2010, Iphone Credit Card Reader Lets You Accept Plastic Anywhere, http://www.wired.com/reviews/2010/02/pr_square_iphone

www.Allelectronic.com

Direct Thermal and Thermal Transfer Book, www.upmraflatac.com

http://www.koehlerpaper.com/en/papier/thermal/anwendungen/etiketten.php, http://www.airplane-ticket.com

http://www.koehlerpaper.com/en/papier/thermal/anwendungen/tickets.php, http://egetfit.com/burgervilles-personalized-calorie-counts-will-other-fast-food-follow/