It Doesn't Hurt to be Informed
An official list of prohibited substances is available for public monitoring. Proposition 65 requires that this list be updated at least once every year, but it's sometimes updated more frequently due to new research and information.
One reason why Proposition 65 passed with such support from voters in California is because it limits consumer exposure to lead in products. Lead can be kind of scary – it's linked to serious birth defects in fetuses and illness in young children and can cause nervous system damage and cancer in adults. Prop 65 now assures that any amount of lead (or other potentially hazardous substances) used in the making of consumer products, no matter how small the amount, is labeled.