California joined 11 others states Wednesday as Gov. Jerry Brown signed a bill to ban bisphenol A (BPA) from baby bottles and sippy cups.

Beginning July 1, 2013, the law will prohibit the manufacture, sale or distribution of bottles or cups designed for children 3 and under that contain BPA at a level above 0.1 parts per billion. The law also requires manufacturers to use the least toxic alternative when replacing BPA.

BPA is a component of hard plastic widely used in shatter-proof plastic baby bottles, sippy cups, and the lining of formula cans and may leach out of these containers into food. 

While animal studies have shown links between tiny amounts of exposure to BPA and subsequent increased risk of cancer, diabetes, reproductive, neurological and developmental disorders, a recent study funded by the Environmental Protection Agency concluded that most of the effects observed in animal studies are probably not relevant to humans because they involved much higher BPA exposures.

The U.S. Food and Drug Administration and the European Food Safety Authority have concluded that BPA is safe at current exposure levels.