Proposition 65, formally known as the Safe Drinking Water and Toxic Enforcement Act of 1986, is a California “right-to-know” law requiring businesses to inform the public about significant exposures to chemicals that cause cancer or reproductive harm. The law aims to empower consumers, but the ubiquity of the label has often led to alarm rather than clarity. This article clarifies the meaning of the P65 warning in the context of food and explains how you can make educated decisions about your consumption.
Decoding the P65 Warning for Food
The P65 warning appears on food products because the law requires notification for any product that results in exposure to one of the over 900 listed chemicals above a certain threshold. The presence of a listed chemical does not mean a product is illegal or unsafe by federal standards; it simply triggers the state’s disclosure requirement. Companies often apply the warning nationally because it is impractical to create separate packaging exclusively for the California market.
Two primary mechanisms cause a P65 warning to appear on food. The first involves naturally occurring substances, such as heavy metals like lead, cadmium, and arsenic, which are absorbed from the soil and water by plants. For example, rice can absorb inorganic arsenic from the environment. The second mechanism involves chemicals introduced during processing, cooking, or through packaging materials.
Acrylamide, a chemical formed when certain plant-based foods are cooked at high temperatures, is a common example of a processing byproduct that can trigger a warning. Additionally, chemicals like Bisphenol A (BPA) or phthalates used in can linings, plastic containers, or equipment can leach into the food product. The warning is based on the chemical’s presence above the state-defined limit, regardless of whether the chemical was intentionally added or is a natural contaminant.
Understanding the Risk Thresholds
The P65 standard uses “safe harbor” levels, which are the No Significant Risk Level (NSRL) for carcinogens and the Maximum Allowable Dose Level (MADL) for reproductive toxins. The NSRL is set at a level calculated to result in no more than one excess case of cancer per 100,000 exposed individuals over a 70-year lifetime.
The MADL for reproductive toxins is set even more conservatively, at 1/1,000th of the level that is shown to have no observable adverse effect. This means the warning threshold is often thousands of times lower than the amount of the chemical that would cause actual harm. A product may be perfectly compliant with federal food safety standards but still require a P65 warning due to this extremely low threshold.
The distinction is between hazard and risk. The warning identifies the hazard—the presence of a listed chemical—but it does not quantify the risk—the probability of harm at the exposure level. Because the P65 levels are set so far below what is generally considered harmful, the warning often indicates a theoretical, rather than an immediate, safety concern. This difference explains why products you consume regularly may carry a P65 warning without being banned or recalled by federal health agencies.
Practical Steps for Informed Consumption
When faced with a P65 warning on food, the most effective strategy for managing exposure is to maintain dietary diversity. Relying heavily on a single food product that carries a warning increases cumulative exposure over time. Rotating your diet by consuming various brands and types of food helps to minimize the intake of any single listed chemical.
If the warning concerns a specific chemical, such as lead or mercury, you can research federal and state health advisories for that substance. The P65 warning typically addresses chronic, long-term exposure, not immediate toxicity from a single serving.
Consumers can also visit the California Office of Environmental Health Hazard Assessment (OEHHA) website, which provides fact sheets for many common chemicals that trigger the warning. This information can help you understand the chemical’s typical sources and health effects, moving beyond the general warning label. Ultimately, the warning provides information that empowers you to make personal choices about your exposure.