Understanding Plastic 6: Polystyrene
Plastic #6 refers to polystyrene (PS), a versatile and inexpensive material used in numerous products. It can exist in both a rigid, clear form (like CD cases) and a familiar, expanded foam version commonly known by the trademarked name Styrofoam. Polystyrene is often used for single-use items, such as disposable hot cups, plates, meat trays, and takeout containers, due to its low cost and insulating properties. However, the use of plastic #6 for food packaging has come under increasing scrutiny due to potential health risks.
The Chemical Concern: Styrene Leaching
The primary chemical of concern with polystyrene is styrene, the compound used to create it. Under certain conditions, styrene can leach from the plastic and contaminate food and drinks. This leaching process is significantly accelerated by heat, such as when hot food or beverages are placed in polystyrene containers, or when the container is microwaved. Contact with acidic foods, fatty foods, or alcohol can also increase the rate of chemical migration. The health implications of styrene exposure are a subject of ongoing research, with some studies linking it to neurotoxic effects and potential carcinogenicity. While the amount of styrene that leaches from a single use is typically low, repeated exposure over time can pose a health risk.
The Dangers of Microwaving Plastic 6
One of the most critical warnings regarding plastic #6 is to never heat it in the microwave. Microwave heating can cause the polystyrene to break down and release higher levels of styrene and other harmful chemicals into the food. Even if a container doesn't visibly melt or deform, chemical leaching can occur at high temperatures. This is particularly problematic for takeout food, where containers are often placed directly in the microwave for reheating without being checked for their material composition. Health experts consistently advise transferring food from plastic #6 containers to microwave-safe glass or ceramic before heating.
Regulatory Standpoints vs. Health Alerts
Regulatory bodies like the U.S. Food and Drug Administration (FDA) have standards for food contact materials and have historically considered polystyrene safe when used appropriately. However, this is based on the assumption of minimal chemical migration under normal conditions and below safety limits. Critics and other health organizations argue that these standards may not fully account for long-term, cumulative exposure or the higher risks associated with improper use, such as microwaving or contact with hot, oily, or acidic foods. Some countries and regions have even banned the use of polystyrene for food packaging entirely. This disparity highlights the importance for consumers to exercise caution and prioritize safer alternatives when possible.
Comparison of Plastic Food Container Safety
| Plastic Code | Type | Food Safety | Microwave Safety | Common Uses |
|---|---|---|---|---|
| 6 | Polystyrene (PS) | NOT safe with heat/oil/acid. Leaches styrene. | NO | Disposable cups, takeout containers, egg cartons |
| 5 | Polypropylene (PP) | Generally safe for food contact. | YES | Yogurt containers, bottle caps, reusable food storage |
| 2 | High-Density Polyethylene (HDPE) | Safe for food storage. | NO (Can degrade) | Milk jugs, juice bottles |
| 1 | Polyethylene Terephthalate (PET/PETE) | Safe for single-use cold food/drinks. | NO (Single-use) | Water and soda bottles |
| Glass / Ceramic | Non-Plastic | Safest option, non-reactive. | YES (If labeled) | Reusable containers, dinnerware |
Safer Alternatives and Handling Practices
Given the potential risks associated with plastic #6, especially with heat, adopting safer food storage and reheating practices is recommended. Consumers have many options to reduce their reliance on polystyrene. Glass containers are a non-reactive and heat-resistant option, suitable for microwaving and long-term storage. Stainless steel containers are another durable and safe alternative. For reusable plastic containers, look for the recycling codes #5 (PP) or #2 (HDPE), which are generally considered safer for food use. For single-use needs, consider products made from compostable or plant-based materials. UCLA Health on Polystyrene Safety
Conclusion
In summary, while plastic 6 (polystyrene) may be acceptable for storing cold, non-acidic foods, it is generally not considered safe for food when heat is involved. The risk of chemical leaching, particularly styrene, into food is significantly increased when polystyrene is heated or comes into contact with hot, fatty, or acidic contents. To prioritize health and safety, it is best to avoid using plastic #6 for microwaving food or for serving hot meals. Switching to reusable containers made from glass, ceramic, or safer plastics like #5 (PP) and #2 (HDPE) provides a more reliable alternative for everyday food handling.
