Thermal receipts and tickets are so ordinary that most of us barely glance at them before they land in a pocket or trash can. Yet those small slips of paper are a major source of contact with chemicals that can disrupt hormones, and they are notoriously hard to recycle safely. A new generation of wood-based coatings, built from plant polymers instead of petroleum-derived additives, now promises a way to keep the convenience of heat-printed paper while sharply cutting the toxic footprint.
Researchers at EPFL have shown that it is possible to turn components of wood into functional coatings that behave like conventional thermal paper, but without relying on the usual bisphenol developers or other problematic substances. If this technology scales, grocery receipts, transit tickets, parking stubs, and even event passes could shift to a safer, more sustainable format that still works with existing printers and workflows.
Why the receipt in your wallet is a chemical problem
For years, scientists have warned that the slip in a shopper’s hand is more than a record of prices. Traditional thermal paper is coated with a mix of dye and chemical developers that react to heat from a printer head, and many of those developers belong to the bisphenol family that can interfere with hormone signaling in the body. When I think about how often cashiers, delivery drivers, and commuters handle these papers, the exposure adds up quickly, especially because the coating can rub off onto skin and then move into the bloodstream.
Those concerns are not hypothetical. Reporting on thermal paper has highlighted that a single receipt can carry enough bisphenol to register in lab tests, and that frequent handling is linked to measurable levels of these compounds in workers’ bodies. One analysis notes that if you have a receipt in your wallet right now, you are carrying more than proof of purchase, because the thermal coating can transfer through touch and even through recycling streams, contaminating other paper products.
How thermal paper works, and why it has been hard to replace
To understand why safer receipts have been slow to arrive, it helps to look at how thermal paper is engineered. Instead of using ink, the paper is coated with a layer that contains a colorless dye and a developer held in a glassy matrix. When a printer head heats tiny spots on the surface, the matrix softens, the dye and developer meet, and a dark mark appears. The chemistry has to be finely tuned so that the paper stays blank in normal conditions, reacts quickly under heat, and then remains legible for months or years without smearing or fading.
That performance checklist has made it difficult to swap in benign ingredients. Many early attempts at “BPA free” receipts simply traded one bisphenol for another, or used alternative developers that still raised toxicology questions or did not hold up in real-world handling. The coatings also need to survive storage in hot cars, exposure to sunlight, and the mechanical stress of printers and cash drawers. As a result, retailers and ticketing systems have stuck with legacy formulations, even as evidence of health and environmental risks has mounted.
EPFL’s wood-based coatings: turning lignin into a developer
The breakthrough from EPFL starts from a different premise: instead of tweaking fossil-derived molecules, the team looked to the structural components of plants. Wood is rich in lignin, a complex polymer that helps give trees their rigidity and resistance to decay. By carefully processing lignin and related wood-derived chemicals, the researchers created a family of developers that can take the place of bisphenols in thermal coatings while still triggering the color change that printers need.
According to Jan, the group did not try to reinvent the entire printing system. They focused on designing a coating that could be applied to standard paper and run through existing thermal printers, so that grocery stores and transit agencies would not need to replace hardware. Reports on the project describe how Researchers at EPFL demonstrated that wood-derived materials can meet the technical requirements for thermal paper, including fast response to heat and compatibility with current devices, while avoiding the problematic developers that tend to leach during handling and recycling.
From lab concept to printable receipts and tickets
What makes this work feel tangible is that it has already moved beyond test tubes into printed samples. The EPFL team coated paper with their lignin-based formulation and ran it through standard thermal printers to generate grocery-style receipts and ticket-like stubs. The resulting prints showed sharp text and logos, with contrast comparable to conventional thermal paper, which is essential if barcodes and QR codes are going to scan reliably at supermarket checkouts or train station gates.
Coverage of the project notes that the researchers have effectively shown a New tech could make grocery receipts and paper tickets from non-toxic wood coatings, with the coatings designed to stay bound to the paper instead of rubbing off easily during use or recycling. That detail matters, because one of the big problems with current thermal paper is that the developer can migrate into recycled cardboard and tissue products, turning an attempt at sustainability into another exposure route.
Stability, sunlight, and the test of time
Performance over time is the next hurdle for any new receipt technology. A coating that prints well on day one but fades in a glove compartment or under a shop window is not going to satisfy retailers, auditors, or customers who need records for returns and warranties. The EPFL team therefore subjected their wood-based coatings to extended storage tests, including exposure near windows where sunlight and fluctuating temperatures can accelerate degradation.
Reports on those trials indicate that the coatings stayed stable when stored near a window for months, and that printed logos remained readable after a year, which is a strong signal that the chemistry can hold up in real-world conditions. One summary notes that the wood-based receipt paper boosts safety while still delivering the durability that businesses expect, with the coatings providing long-term legibility without relying on problematic chemicals. The description of how the coatings stayed stable under light and heat is especially important for tickets and parking slips that are often left on dashboards or in wallets for extended periods.
Health and environmental stakes of moving beyond BPA
The potential health benefits of a safer coating are straightforward. If the developer is built from lignin and related wood-derived molecules instead of bisphenols, the risk of hormone disruption from handling receipts should drop significantly. That is particularly relevant for cashiers and other workers who touch hundreds of slips per shift, often without gloves, and for children who may play with or chew on paper that comes home in shopping bags. While any new material still needs thorough toxicology review, starting from plant polymers that are already part of natural ecosystems is a very different baseline from synthesizing new endocrine-active compounds.
There is also a recycling angle that I find hard to ignore. Conventional thermal paper contaminates mixed paper streams, because the developer can leach out during pulping and end up in cardboard boxes, paper towels, or napkins. By contrast, the EPFL approach is designed so that the wood-based developer remains bound to the fiber matrix and does not migrate as easily during processing. Coverage of the project emphasizes that this New tech could make grocery receipts, paper tickets that are not only safer to touch but also less likely to spread chemicals through handling and recycling processes, which would be a meaningful win for municipal waste systems.
A new way to make receipts without BPA, using plant chemistry
One of the more intriguing aspects of the EPFL work is how it reframes the design problem. Instead of starting from scratch with entirely novel molecules, the researchers looked at how plants already manage color, stability, and structural strength. Lignin, tannins, and other wood-derived compounds have rich chemistry that can be tuned to interact with dyes in predictable ways. By adjusting how these molecules are processed and combined, the team created a developer that activates under heat but remains inert under normal conditions, which is exactly what thermal paper needs.
Reporting on the project describes this as a New Way to Make Receipts Without BPA, with the scientists emphasizing that they did not simply swap one synthetic developer for another. Instead of relying on the usual bisphenol interaction between the dye and developer, they engineered a different pathway rooted in plant chemistry. One account notes that Instead of starting from scratch, the team drew on materials that plants already use to manage light and structure, then adapted those for the thermal printing context.
From lab bench to checkout counter: what adoption might look like
Even with promising lab data, shifting the global receipt and ticket ecosystem is not automatic. Thermal paper is a commodity product, and printers in supermarkets, parking meters, and ticket kiosks are tuned to specific paper grades. The EPFL team appears to have anticipated this by designing coatings that can be applied using existing industrial processes and that behave similarly to current products in printers. That compatibility could lower the barrier for manufacturers who might otherwise hesitate to retool their lines or risk printer jams and misprints.
Scaling up will still require partnerships with paper mills, coating companies, and the retailers and transit agencies that buy huge volumes of rolls each year. Jan and the other researchers have already shown that their approach can produce receipts and tickets that meet technical requirements, but commercial adoption will hinge on cost, supply of wood-derived feedstocks, and regulatory pressure on bisphenols. As more jurisdictions scrutinize thermal paper and as evidence of hormone disruption from current coatings accumulates, the case for switching to a wood-based alternative that has been validated by New tech from EPFL is likely to become harder for industry to ignore.
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