Part 1: The Invention of Bisphenol A
Bisphenol A was first synthesized in 1891 by Russian chemist Aleksandr Dianin, who was experimenting with condensation reactions between acetone and phenol. The compound sat largely unused for decades — a chemical curiosity with no obvious application.
That changed in the 1930s. British biochemist Edward Charles Dodds was researching synthetic estrogens — compounds that could mimic the hormone estrogen in the human body. In 1936, Dodds identified BPA as a synthetic estrogen. Ironically, he also discovered diethylstilbestrol (DES) around the same time, which became the first widely prescribed synthetic estrogen — and later one of the most notorious pharmaceutical disasters in history.
BPA's estrogenic properties were noted and then largely set aside. What happened next determined the chemical's fate for the next century.
Part 2: How BPA Is Made
BPA is produced by combining two molecules of phenol with one molecule of acetone in the presence of an acid catalyst — typically hydrochloric acid or an ion-exchange resin. The reaction is straightforward and inexpensive, which is why BPA became one of the highest-volume chemicals in industrial production.
The resulting compound — 2,2-bis(4-hydroxyphenyl)propane — is a white crystalline solid at room temperature. Its molecular structure is what makes it both useful and dangerous: two phenol rings connected by a carbon bridge, a shape that closely mimics the molecular geometry of estradiol, the primary form of estrogen in the human body.
Global production of BPA today exceeds 10 million metric tons per year, making it one of the most widely manufactured chemicals on earth.
Part 3: Why We Started Using Bisphenols
In the 1950s, chemists discovered that BPA could be polymerized into polycarbonate plastic — a material that was strong, transparent, lightweight, and heat-resistant. Around the same time, it was found that BPA combined with epichlorohydrin produced epoxy resins with exceptional adhesive and protective properties.
These two discoveries launched BPA into industrial ubiquity:
Polycarbonate plastics made from BPA became the material of choice for baby bottles, water bottles, food storage containers, eyeglass lenses, CDs and DVDs, medical devices, and automotive components.
Epoxy resins containing BPA were applied as protective linings inside food and beverage cans, water supply pipes, and dental sealants — putting BPA in direct contact with food and drinking water for billions of people.
Thermal paper manufacturers discovered that BPA acted as a color developer in heat-sensitive coatings. When the heated print head of a thermal printer contacted the BPA-coated paper, it triggered a chemical reaction that produced a visible mark — no ink required. The simplicity and low cost of this system made it the standard for receipt printing worldwide.
By the late 20th century, BPA was essentially everywhere in modern life.
Part 4: What Products Contain Bisphenols
BPA and its substitutes (primarily BPS and BPF) are found in a vast range of products:
Food contact materials: Can linings, bottle caps, food storage containers, microwave-safe plastics, coffee maker components, water cooler jugs.
Thermal paper: Point-of-sale receipts, ATM receipts, airline boarding passes, lottery tickets, parking tickets, fax paper, prescription labels.
Medical devices: IV tubing, dialysis equipment, dental composites and sealants, medical instrument housings.
Consumer electronics: CDs, DVDs, Blu-ray discs, eyeglass lenses, smartphone components, printer components.
Construction materials: Pipe linings, flooring, adhesives, protective coatings.
Personal care products: Some nail polishes, hair products, and sunscreens have been found to contain bisphenol compounds.
The thermal paper application is particularly significant from an exposure standpoint because — unlike a can lining or plastic bottle — receipt paper transfers bisphenols directly to skin on contact, with no barrier between the chemical and the body.
Part 5: How We Determined the Health Impacts
Scientific concern about BPA's biological activity began to re-emerge in the 1990s, driven by a series of accidental discoveries and deliberate investigations.
The accidental discovery (1993): Researchers at Stanford University noticed that yeast cells in their lab were behaving as if exposed to estrogen. The source was traced to polycarbonate flasks that had been autoclaved — the heat had caused BPA to leach out of the plastic and into the cell culture medium. This serendipitous finding launched a new wave of research.
Animal studies (1990s–2000s): Dozens of studies in rodents demonstrated that BPA exposure — even at low doses — caused measurable changes in reproductive development, prostate size, breast tissue, behavior, and metabolic function. The doses causing effects were often far below the "safe" levels established by regulatory agencies.
The low-dose controversy: Traditional toxicology operates on the principle that "the dose makes the poison" — higher doses cause more harm. Endocrine disruptors like BPA challenged this model. Some studies found that very low doses of BPA produced different — and sometimes more pronounced — effects than high doses, because the body's hormone receptors are designed to respond to extremely small concentrations of signaling molecules.
Human biomonitoring: The US Centers for Disease Control began measuring BPA in human urine as part of the National Health and Nutrition Examination Survey (NHANES). Their findings, published in 2004, were striking: BPA was detectable in the urine of more than 90% of Americans tested, confirming widespread exposure across the general population.
Cashier studies: A landmark 2014 study published in PLOS ONE measured BPA levels in the urine of cashiers before and after work shifts. Cashiers who handled thermal receipts showed significantly elevated urinary BPA compared to those who did not — and the effect was dramatically amplified when cashiers used hand sanitizer before handling receipts.
Part 6: Documented Health Outcomes
The body of research linking bisphenol exposure to adverse health outcomes has grown substantially over three decades. The following associations have been documented in peer-reviewed literature:
Reproductive and developmental effects: Altered reproductive development in animal models, reduced sperm quality in men with higher BPA exposure, disrupted menstrual cycles, earlier onset of puberty in girls, and adverse pregnancy outcomes have all been associated with bisphenol exposure in epidemiological studies. Among the most studied effects is the impact on fertility specifically — see our full article on BPA, BPS, and fertility for a detailed look at what the research shows.
Cardiovascular disease: A 2008 study in JAMA found that higher urinary BPA concentrations were associated with increased rates of cardiovascular disease, diabetes, and liver enzyme abnormalities in a large sample of US adults — an association that held after controlling for age, sex, race, and other risk factors.
Metabolic disruption: BPA has been linked to obesity, insulin resistance, and type 2 diabetes in both animal models and human epidemiological studies. The proposed mechanism involves BPA's interference with pancreatic beta cell function and adipocyte differentiation.
Neurological effects: Animal studies have demonstrated that prenatal BPA exposure alters brain development and behavior, including increased anxiety, altered learning and memory, and disrupted social behavior. The developing brain is considered particularly vulnerable.
Cancer: BPA's estrogenic activity has led researchers to investigate its role in hormone-sensitive cancers. Laboratory studies have shown BPA can stimulate the proliferation of breast cancer cells and prostate cancer cells. Epidemiological evidence remains under active investigation.
BPS: Same risks, less research: BPS, the most common BPA substitute in thermal paper, has been studied far less extensively — but the available evidence is not reassuring. Multiple studies have found BPS to be an equally potent estrogen receptor agonist. A 2013 study found BPS caused the same pattern of developmental disruption in zebrafish embryos as BPA at equivalent doses.
Part 7: The Global Regulatory Response
Recognition of bisphenols' health risks has translated into regulatory action at varying speeds in different jurisdictions.
Baby bottles — the first wave (2008–2012): Canada became the first country to declare BPA a toxic substance in 2008 and banned it from polycarbonate baby bottles. The European Union followed in 2011, and the United States FDA banned BPA in baby bottles and sippy cups in 2012 — though notably, the FDA action was largely symbolic, as manufacturers had already voluntarily removed BPA from these products due to consumer pressure.
Food contact materials: The EU has progressively restricted BPA in food contact materials, with a near-total ban on BPA in food contact plastics taking effect in 2023 under Regulation (EU) 2023/1543. France banned BPA in all food contact materials in 2015.
Thermal paper — the most recent frontier: Thermal receipt paper became a regulatory focus after research confirmed that dermal absorption from receipts represented a significant and largely unrecognized exposure pathway.
The EU restricted BPA in thermal paper in 2020 under REACH regulations, effectively requiring the industry to switch to alternatives. However, the most common replacement — BPS — was not initially covered by the restriction, leading to widespread substitution with an equally problematic compound.
In the United States: Connecticut was the first US state to restrict BPA in thermal paper (2013), but the law exempted BPS, rendering it largely ineffective.
Washington State passed the most comprehensive US legislation to date — a ban on all bisphenol compounds (not just BPA) in thermal paper, effective 2026. This closed the BPS loophole that undermined earlier regulations. For a plain-English overview of what the law requires and how businesses can comply, see our Washington State compliance guide.
California's AB 1604, currently pending, would extend similar protections statewide. If passed, it would cover the largest economy in the US and effectively set a national standard.
International bans: Beyond the US and EU, Japan has significantly reduced BPA in food contact materials through industry agreements. Several Scandinavian countries have implemented restrictions exceeding EU minimums. Australia and New Zealand have restricted BPA in baby products. China has restricted BPA in infant formula packaging.
Part 8: What Thermal Paper Uses Instead
The shift away from bisphenol-based thermal paper has produced several alternative technologies:
BPS-based thermal paper ("BPA-Free"): The most common immediate substitute. BPS functions identically to BPA as a color developer and produces paper that is visually indistinguishable from BPA paper. As discussed throughout this site, BPS carries essentially equivalent health risks to BPA. This substitution represents a failure of regulatory design — restricting a specific chemical rather than a class of chemicals with similar properties.
Phenol-free thermal paper: A genuinely safer alternative that replaces bisphenol color developers with alternative chemical systems. The most commercially successful example is Blue4est, developed by Koehler Paper in Germany. Blue4est uses a proprietary dye-based system that requires no bisphenol compounds and produces paper with a characteristic blue-grey tint. It is approved for use in food contact applications and has passed extensive toxicological screening. Blue4est is now used by major retailers and banks in Europe and is increasingly available in North America.
Other phenol-free systems: Several other manufacturers have developed phenol-free thermal paper using vitamin C (ascorbic acid) based developers or other non-toxic chemistry. These products are less widely distributed than Blue4est but represent the same approach.
Digital receipts: The most complete solution is eliminating paper receipts entirely. Email, SMS, and app-based digital receipts have become standard options at major retailers. Several jurisdictions have introduced or are considering legislation requiring merchants to offer digital receipt options. From a health standpoint, digital receipts eliminate the exposure pathway entirely for both workers and customers.
The transition challenge: Switching to phenol-free paper requires no changes to existing thermal printers — the paper is a drop-in replacement. The primary barriers are cost (phenol-free paper carries a modest price premium) and supply chain inertia. As regulations expand and consumer awareness grows, the economic case for phenol-free paper continues to strengthen.
A growing number of major US retailers have proactively switched ahead of regulation. See our 2026 Retailer Scorecard for the full list.