Prop 67 defines single-use plastic carryout bags as any bag ranging from 0.5 millimeters thick to 2.25 millimeters thick. A reusable bag, on the other hand, is specified to be at least 2.25 millimeters thick and capable of carrying 22 pounds for a minimum of 125 uses. By setting a minimum requirement of at least 2.25 mm for the reusable bags, the amount of virgin plastic used per bag and the resulting carbon footprint is higher than what was needed to produce thin single-use plastic carryout bags.
Some counties in California experienced with single-use bag ordinances suggest that reusable bags be produced above the minimum requirement—at least four millimeters thick—to ensure reuse. Additionally thick reusable plastic bags must be used a minimum of five times to offset the carbon emitted just to produce the plastic.
A requirement that reusable plastic bags must be capable of a minimum of 125 uses seems great on paper, but how does one regulate and monitor consumers’ use of reusable bags? In March of 2013, Austin, Texas implemented a Single-Use Carryout Bag Ordinance (SUBO) similar to the one California just passed. In 2015, the Austin Resource Recovery Division presented a two-year study on the environmental effects the SUBO had on the city. Although the amount of single-use plastic carryout bags was reduced within the city, the study concluded that “there have been unintended consequences, such as an increase in reusable plastic bags in the recycling stream.”
Similarly, a study in Monterey County surveyed 740 shoppers post implementation of a SUBO and found that only four shoppers ever reused the reusable carryout bags available for purchase at checkout. Others argue that the ten cent tax on the purchased plastic bags is not a strong enough incentive to reuse the bags or stop using plastic bags altogether.
However, some early results are showing that shoppers may be reducing the number of plastic bags used overall. In a recent effectiveness study, San Jose found twice as many people opted not to take a bag post-ban for small numbers of items, and saw decreases in the number of plastic bags found in litter and creek cleanups.