California Proposition 67 passed by a 52 - 48 margin, thus enabling the requirements of Senate Bill 270 to immediately take effect. A companion piece supported by the plastic bag industry, Proposition 65, would have required monies that grocers take in for selling non-plastic bags be directed to environmental causes. That measure failed, with 55% of the vote opposing it.
Photo By Andrea Westmoreland from DeLand, United States (Great Blue Heron Swallows Fish in Plastic Bag!) [CC BY-SA 2.0 (http://creativecommons.org/licenses/by-sa/2.0)], via Wikimedia Commons
For those in the dark about the issue, or, those who simply question why it is such an important environmental issue, here is a good source of information to learn why it was enacted: Plastic Ban Info