FoodScience of Vermont do not add lead to their products. The warning stated on the label regarding lead is known as Proposition 65. Proposition 65 requires businesses to notify Californians about any chemicals in the products they purchase. These products include food items including everything from fruit and vegetables, restaurant food, water, and dietary supplements.
Because FoodScience sell to California and because there may be trace amounts of naturally occurring lead in the minerals (that come from the earth) used in their products, they are required to provide a "clear and reasonable" warning. For more information on Proposition 65 please visit: http://oehha.ca.gov/prop65/background/p65plain.html