Bisphenol A (BPA) is a chemical compound used since the 1950s to manufacture certain plastics and resins. It is primarily found in polycarbonate plastics and epoxy resins, which are widely used in consumer goods, including food and beverage containers. Concern stems from the chemical’s ability to leach out of these materials and into the contents they hold, particularly when containers are heated or damaged. Understanding how to identify which plastics contain this substance is a practical step consumers can take to manage their exposure. This guide outlines the system used to categorize plastics and points out which types are naturally free of BPA.
What is BPA and Why the Concern?
BPA is valued in manufacturing for its ability to make plastics hard, clear, and durable, leading to its historical use in items like hard plastic water bottles. The primary health concern is its classification as an endocrine disruptor, meaning the chemical can mimic the structure and function of the body’s natural hormones, specifically estrogen.
By imitating estrogen, BPA can bind to hormone receptors and potentially interfere with normal bodily processes, including growth, cell repair, and fetal development. Exposure is concerning for infants, children, and developing fetuses because of their higher sensitivity and rapid developmental changes. While the U.S. Food and Administration (FDA) states that current low-level exposure is safe, many health organizations advise caution due to the potential for hormonal interference.
The Plastic Resin Identification Codes
To help consumers and recycling facilities identify the type of plastic used in a product, the Resin Identification Code (RIC) system was established. This code is represented by the familiar triangle symbol with a number inside, typically found molded into the bottom of a plastic item. The system uses numbers 1 through 7, with each number corresponding to a specific polymer.
Although the RIC system was originally designed to streamline plastic recycling, it is now the most accessible tool for consumers to assess a product’s chemical composition. The number identifies the primary plastic resin used. Knowing which number corresponds to which plastic type is key to making informed choices about BPA exposure.
Inherently BPA-Free Plastic Types
Certain plastics are naturally BPA-free because their chemical building blocks do not involve Bisphenol A. Consumers can confidently select items marked with codes 1, 2, 4, and 5 for food and beverage contact, as these represent the safest choices for avoiding BPA leaching.
Code 1: Polyethylene Terephthalate (PET or PETE)
This plastic is used for most single-use water and soda bottles.
Code 2: High-Density Polyethylene (HDPE)
HDPE is a stiffer, opaque plastic commonly found in milk jugs and detergent bottles.
Code 4: Low-Density Polyethylene (LDPE)
LDPE is a flexible material used for plastic bags and squeeze bottles.
Code 5: Polypropylene (PP)
Polypropylene is durable and heat-resistant, making it one of the safest materials for food storage. It is frequently used for yogurt tubs, some reusable food containers, and medicine bottles.
Plastics to Approach with Caution
Plastics with codes 3, 6, and 7 require attention as they may contain concerning chemicals, including BPA. Code 7, labeled “Other,” is the main category of concern for BPA avoidance because it includes Polycarbonate (PC) plastic. Polycarbonate traditionally used BPA for hardness and clarity, and this code is often found on older hard plastic water bottles and certain food storage containers.
Unless a Code 7 item is explicitly labeled “BPA-free,” it should be avoided for food and drink, as it may contain the chemical. The “BPA-free” label does not guarantee safety, however, as manufacturers often replace BPA with similar bisphenol compounds like Bisphenol S (BPS) or Bisphenol F (BPF). Studies indicate that these substitutes also function as endocrine disruptors, possessing hormonal activity comparable to BPA.
Code 3 (Polyvinyl Chloride or PVC) and Code 6 (Polystyrene or PS) are less likely to contain BPA but are avoided for other reasons. PVC plastics often contain phthalates, which are also endocrine-disrupting chemicals. Polystyrene, used in Styrofoam and disposable take-out containers, can leach styrene, a suspected carcinogen, particularly when heated.