Polyethylene terephthalate, commonly known as PET or PETE, is the plastic identified by the #1 recycling code found on the bottom of containers. This material is used widely in the packaging industry, particularly for holding beverages and food items. PETE’s popularity stems from its desirable properties, which include being lightweight, shatterproof, and having good barrier qualities. Given its pervasive use in items like single-serving water and soda bottles, the question of PETE’s safety for general consumer use is a frequent concern. This article evaluates the scientific evidence regarding the safety of PETE plastic, focusing on chemical leaching and the practical factors that can influence its stability.
What PETE Plastic Is and Its Common Uses
PETE is a thermoplastic polymer, meaning it can be heated and molded into various shapes. Chemically, it is a type of polyester, made from the combination of ethylene glycol and terephthalic acid. This structure gives the material high tensile strength and resistance to impact, making it a robust alternative to glass. It also possesses favorable gas and moisture barrier properties, which are important for maintaining product freshness and carbonation in drinks.
The material is transparent and lightweight, allowing consumers to easily see the contents while minimizing transportation costs. PETE is the material of choice for virtually all single-serving and two-liter soft drink bottles, as well as most bottled water. Beyond beverages, it is also frequently molded into containers for products like peanut butter, salad dressings, cooking oils, and various household cleaners.
Scientific Assessment of Chemical Leaching
The primary safety concern with PETE plastic involves the potential for chemicals to migrate, or leach, from the plastic into the contents. The two substances most frequently studied are antimony and acetaldehyde. Antimony, typically in the form of antimony trioxide, is a catalyst used in the manufacturing process to speed up polymerization. While most remains locked within the polymer structure, trace amounts can migrate into the liquid over time.
Scientific studies have consistently shown that under normal storage conditions, the levels of antimony that leach into bottled water or beverages are extremely low. These concentrations are measured in parts per billion (ppb) and remain well below the maximum contaminant levels established by regulatory bodies for drinking water. Another compound, acetaldehyde, is a trace byproduct of the PETE manufacturing process that can impart a slightly sweet taste to water, but the amounts detected are not considered to pose a health risk. PETE plastic is not manufactured with Bisphenol A (BPA), which is typically associated with other plastics like polycarbonate (labeled with the #7 recycling code).
Factors That Influence PETE Safety
While PETE is considered safe under standard conditions, certain environmental and usage factors can increase chemical migration. Temperature is the most significant factor, as heat accelerates the movement of chemical components from the plastic matrix into the contents. Storing PETE bottles in high-temperature environments, such as a hot car or direct sunlight, can significantly increase the leaching of antimony. Studies indicate that antimony leaching begins to increase noticeably above 45°C (113°F) and rises sharply at temperatures of 60°C (140°F) or higher.
The duration of storage is another factor, as chemical migration is a time-dependent process. Products stored in PETE containers for long periods, especially approaching their expiration date, may exhibit slightly higher levels of leached compounds than freshly bottled products. Furthermore, repeatedly reusing single-use PETE bottles is discouraged. Repeated washing, abrasive cleaning, and physical wear can cause surface degradation, which compromises the polymer and may increase the potential for chemical release and microbial growth.
Regulatory Standards and Safe Handling Practices
Polyethylene terephthalate is recognized as safe for food contact by major international regulatory agencies. The U.S. Food and Drug Administration (FDA) has approved PETE for use in food and beverage packaging, concluding that the material does not leach harmful chemicals under intended conditions of use. Similarly, the European Food Safety Authority (EFSA) has established strict guidelines and safety assessments for both virgin and recycled PETE materials used in food contact applications.
To minimize potential risk, consumers should follow simple handling practices. It is advisable to avoid leaving PETE bottles in high-heat environments like sunlit windows or hot vehicles. Consumers should also respect the single-use designation of most PETE containers, opting not to refill them extensively for long-term use. Finally, proper disposal by placing the plastic in the #1 recycling bin helps ensure the material can be processed safely into new products.