Palo Alto's crusade against plastic bags will significantly expand in the coming months as city officials plow forth with a plan to ban the rustling creek polluters from local stores and restaurants.

The city is preparing to perform an in-depth analysis to determine the impacts of expanding its existing plastic-bag ban, which applies only to local supermarkets. That ban, which went in effect in September 2009, prompted a legal challenge from the industry group, Save the Plastic Bag Coalition. As part of its settlement with the group, the city had agreed to perform an Environmental Impact Report before the ban could be expanded to other local establishments.

Now, Palo Alto is doing just that. According to a new report from the Public Works Department, the city is preparing to study the proposal, which would also require businesses to charge patrons for paper bags. Julie Weiss, an environmental specialist in the Public Works Department, wrote in a newly released report that plastic bags continue to pile up at local creeks, even after the 2009 ban.

"Bags are easily blown into waterways, across city boundaries and from freeways, and are consistently found during creek cleanups," Weiss wrote. "They are designed to hold products for a short period of time but essentially do not decompose in natural environments."

In targeting plastic bags, Palo Alto has plenty of company. Weiss noted that 48 cities in California have passed laws restricting plastic bags. Most of these, she wrote, also require a charge for paper bags. These charges are usually between 10 cents and 25 cents per bag.

Around Santa Clara County, San Jose has emerged as a forerunner in the field. The city has banned plastic bags at retail establishments, though the ban does not extend to the food-service industry. San Mateo County has also embarked on an effort to limit plastic bags. The county is leading an effort to conduct its own Environmental Impact Report on plastic-bag restrictions, an analysis from which other cities would be able to craft local ordinances. This effort has drawn participation from a number of cities in San Mateo and Santa Clara counties, including Menlo Park, Mountain View, East Palo Alto, Redwood City, Woodside and San Mateo.

Palo Alto is performing its own study because of its 2009 settlement with the Save the Plastic Bag Coalition. The industry group has contended that the city's ban is ill-founded because of the high environmental cost of producing more paper bags.

One of Palo Alto's major goals is to get people away from both paper and plastic and to promote reusable bags. The city has seen the percentage of customers using reusable bags rise from 9 percent to 19 percent after the 2009 grocery-store ban. However, that percentage has hit a plateau, according to the new Public Works report.

"Given the ubiquitous nature of plastic bags and their negative contribution to pollution in the local and global environment, staff seeks to expand the current ban to include all retail and food-service establishments and to establish a store charge for paper bag use with the goal of incentivizing consumers to use reusable bags in lieu of single-use paper or plastic," Weiss wrote.

Phil Bobel, assistant director of Public Works, said the city is particularly concerned about small, take-out restaurants whose bags often end up in local creeks. Bobel told the Weekly that the city plans to begin its outreach to local restaurants and retailers in the coming months with the goal of getting the ban in place by April 22, 2013, which is Earth Day. Feedback from restaurants and retail establishments would help refine the proposal.

Public Works staff also plans to bring the draft Environmental Impact Report for the expanded ban to the City Council by September.

"It was always part of the plan that the ban on plastic bags at grocery stores would be step one," Bobel said.