Napa Valley Olive Oil:

California state Senate Bill SB920 in 1997 amended the state's Health and Safety code relating to food labeling. It required that any olive oil produced, processed, sold, offered for sale, given away, or possessed in this state adhere to the following: Sonoma Valley, Napa Valley, etc, Oil labeled with one of the approved American Viticultural Areas under federal law (ex: Sonoma Valley), to be made of oil, 75% of which is derived from olives grown in that area.