What is Bisphenol A?
Bisphenol A, commonly known as BPA, is an industrial chemical that has been used to make certain plastics and resins since the 1960s. It is primarily used in the production of polycarbonate plastics and epoxy resins. Some of the products that may contain BPA include food and beverage containers, water bottles, sports equipment, dental sealants and composites, eyeglass lenses, and protective coatings on metal products like food cans, bottle tops and water supply lines.

How are we exposed to BPA?
We are exposed to small amounts of BPA through our everyday use and contact with products made from BPA-containing plastics and resins. The major routes of exposure include:

- Through our diet: When plastics containing BPA are used in food and beverage packaging, a very small amount of BPA can leach out and enter foods and beverages. This leads to ingestion of BPA when we consume these foods and liquids.

- Absorption through the skin: BPA is able to migrate out of plastic products upon contact and penetrate the skin, especially if handled when hot or moist. This can result in dermal absorption of BPA during bathing, showering, or using BPA-containing cosmetics.

- Inhalation of household dust: Since BPA breaks down into fine particles over time, indoor dust and air may contain BPA residues from degraded plastic products. Inhalation of contaminated dust and air results in low level BPA exposure.

- Medical and dental procedures: Some dental seals, composites, sealants, and protective coatings used during medical and dental treatments may contain BPA. This leads to accidental ingestion or absorption.

Is BPA harmful?
There is ongoing scientific debate regarding the health effects of low doses of BPA that we are typically exposed to through our daily lives. However, accumulating evidence from both animal and human studies suggests that BPA may disrupt the endocrine system and cause adverse developmental and health effects. Some key concerns are:

- Endocrine disruption: Studies show that BPA can mimic the effects of estrogen, a female sex hormone, and interfere with the body's endocrine system. This has raised concerns about links to reproductive health issues, breast and prostate cancer, obesity, and other illnesses.

- Effects on brain development: BPA exposure during fetal development and childhood has been associated with behavioral changes, hyperactivity, and changes in the structure of the brain in animal studies. This is a concern since humans could be exposed to BPA in utero or as infants and small children through liquid formula packaging and other sources.

- Other health impacts: Epidemiological research has tied BPA exposure to cardiovascular disease, diabetes, liver toxicity, and other metabolic disorders in adults as well as reproductive issues like erectile dysfunction, early puberty onset, and disruption of menstrual cycles.However, more research is still needed to clarify these possible links.

Toxicity depends on dose and route of exposure. High doses, such as through accidental ingestion or occupational exposure, can potentially cause direct toxicity. However, evidence suggests that even minute traces of BPA, at levels within safety limits, may interfere with hormone signaling pathways and cellular processes in a way that contributes to disease development over a lifetime of exposure. Fetuses, infants, and children are considered especially vulnerable due to their ongoing development.

Regulation of BPA
Due to the growing health concerns, several regulatory organizations have taken steps to restrict the use of BPA in certain products that may increase human exposure. Some key regulatory actions taken are:

- In the US, the FDA banned the use of BPA in baby bottles and sippy cups in 2012. However, it continues to declare BPA safe at current exposure levels from other sources.

- The EU has classified BPA as a reproductive toxicant since 2008 and restricted its use in baby bottles. Many EU countries have additional prohibitions for BPA in food contact materials for children under 3 years.

- Canada considered BPA toxic in 2010 and prohibited its use in polycarbonate drinking bottles for children under 2 years.

- Some manufacturers have voluntarily stopped using BPA in their food packaging due to safety concerns even where not mandated by regulations.

However, BPA continues to be used heavily in other products globally and complete bans are yet to be imposed. Concerns remain on potential unintended exposures through various sources. More research is also needed to determine safe exposure limits, specific health risks, and alternative safer materials that can replace BPA in the long run.

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