California Proposition 65 is a labeling law, not a product-safety standard in the usual sense. It requires businesses to warn California consumers when a product exposes them to a chemical on the state’s list above a defined level. For drinkware, the chemicals most often involved are lead and cadmium in coatings, decoration, or the base material.

Safe-harbor levels

The law sets safe-harbor thresholds: an NSRL (No Significant Risk Level) for carcinogens and a MADL (Maximum Allowable Dose Level) for reproductive toxins. A product below the threshold needs no warning; a product above it must carry one. The chemical list is maintained by California’s Office of Environmental Health Hazard Assessment, and the warning format is set by regulation. These thresholds are deliberately conservative.

A warning does not equal unsafe

A Prop 65 warning means a listed chemical is present above a very conservative threshold, not that the product is unsafe. Many everyday products carry the warning because the threshold sits far below levels most regulators consider hazardous. Even so, a warning on a child’s bottle will alarm retail buyers and end consumers. For a brand seller the decision is commercial as much as technical, because a label on a premium product can affect conversion even when the product is fully safe.

Exporters effectively choose between two approaches:

Practical takeaway: Decide up front whether to test for Prop 65 exemption or to label, and put that decision in your purchase agreement so the factory and lab work to the same target.