The Pew Charitable Trusts

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Since San Francisco enacted the nation's first ban on plastic grocery bags in 2007, dozens of cities have followed with their own bans, regulations or taxes on the lightweight bags, which have a way of blowing into tree branches and waterways. At least 24 states have considered similar legislation, but so far, the movement has stalled in the statehouses.

That may be about to change. A bill that would ban plastic bags in California has made it through the state Assembly and Governor Arnold Schwarzenegger has hinted that he will sign the measure if it passes the Senate. The bill, AB 1998 , would create the first statewide ban on plastic bags in grocery and convenience stores. It also would require the retailers to offer recycled paper bags for sale, at a price of at least 5 cents each. Julia Brownley, the bill's sponsor in the Assembly, says the intent is to encourage shoppers to bring their own reusable bags to the store.

AB 1998 boasts a long list of supporters, including environmentalists who view plastic bags as a symbol of throwaway culture, as well as local governments and waste management groups who are concerned about reducing waste and litter. Importantly, the bill enjoys the endorsement of grocers, who typically have opposed plastic bag bans because paper bags are more expensive to supply.  The California Grocers Association prefers the statewide measure to an ever-changing patchwork of local regulations. It also doesn't hurt that grocers stand to pocket a few pennies on each paper bag they sell.

Brownley has tried similar measures in recent years, including a 25-cent fee on all grocery bags, but has never seen the broad backing her proposal is getting this year. She attributes the support in part to a growing desire to create a uniform statewide policy as more localities push for their own bag regulations.

The plastics industry has been lobbying against the ban. So has the paper industry — although paper bags stand to gain market share, manufacturers don't like the bill's requirement that the bags be made from 40 percent post-consumer recycled material. "If California passes this bill," says Patrick Rita, spokesperson for the Renewable Bag Council, a paper industry group, "we're going to see a real opening up of floodgates on copycat legislation."

Industry groups aren't alone in the battle over bags. Some consumers are arguing to keep the convenience of having free plastic bags at every checkout, while others say plastic bags are useful for lining trashcans, carrying lunch to work or picking up after pets. Limited-government activists also oppose the bill, as do some people who say California's priorities are out of order. As the headline of an editorial in Sacramento's Capitol Weekly put it: "$20 billion in debt, 12 percent jobless, no budget — and we ban grocery bags?"

Playing hardball

As the debate heats up, "paper or plastic?" has become more than a mundane supermarket question.

The American Chemistry Council, which represents a variety of industries including plastics manufacturers, has denounced AB 1998 as a $1 billion bag tax, even though the nickel charge on paper bags would go to retailers rather than the state. The industry also is preparing to fight legislation in Oregon, where four state legislators plan to introduce a plastic bag ban next year.

Like the bill in California, the Oregon proposal has gained critical support from grocers by requiring stores to charge at least 5 cents for paper bags, rather than give them out for free. State Senator Mark Hass, one of the plan's sponsors, says he hopes the nickel charge would be enough of a "pin prick" to get shoppers to remember to bring reusable bags when they go to the store.

Hass expects heavy lobbying from the American Chemistry Council. He has asked the city of Portland to hold off on passing a local plastic bag ban, in order to avoid what happened in Seattle in 2008: The Seattle city council passed a 20-cent tax on grocery bags, only to see the chemistry council sponsor a successful local referendum to overturn it the following year.  "I know they're not afraid to spend money and do whatever they can to prevail," Hass says. "I'm certain they won't sit quietly through this."

Tim Shestek, senior director of state affairs for the American Chemistry Council, says stepping up plastic bag recycling programs is a viable alternative to the more drastic approach some cities are trying. Advocates also have been arguing that plastic bags are more environmentally friendly than paper because the production and transport of paper bags produces more greenhouse gases. "If you're going to restrict plastic bags and force people to use paper," Shestek says, "there are some environmental impacts that people overlook."

Pick your poison

The answer to the paper-or-plastic question may simply depend on which environmental factor you care about most.

The contention that paper bags create more greenhouse gases than plastic was backed by a report by the Florida Department of Environmental Protection, published in February. But the paper industry counters that such calculations do not consider the greater capacity of paper bags. You need three plastic bags to carry the same amount of groceries as one paper bag, which evens out the comparison, paper proponents say.

If wastefulness and landfill capacity is the issue, the picture is mixed here, too. Although paper bags make up only 15 percent of the grocery bags used nationwide, they occupy more landfill space than plastic bags. According to a 2008 waste characterization study by the California Integrated Waste Management Board, plastic bags made up 0.3 percent of the state's disposed waste stream, compared with 0.4 percent for paper bags. On the other hand, plastic bags may linger in landfills for up to 1,000 years, while paper bags break down in landfills in about a month.

Much of the focus on plastic bags has come from their tendency to end up stuck in trees, along roadsides, in rivers and in the ocean. In Washington, D.C., the city's environment department studied the litter in the Anacostia River and determined that about 25 percent of the trash pieces greater than one square inch in size were plastic bags. (The city has passed a 5-cent tax on both paper and plastic grocery bags.)

Finally, there's the question of natural resources. The manufacture of paper bags can involve chopping down trees. Most plastic bags used in the United States are made from petroleum, a non-renewable resource. Although both types of bags are increasingly made from recycled materials, the average recycled content of paper bags is greater.

Rise of reusables

Most environmentalists, including California's Brownley, agree that the answer to cutting back on landfill volume, litter, greenhouse gases and natural resource depletion, is to use neither paper nor plastic but to shop with reusable bags instead. But lately, the plastics industry has been targeting that notion, too.

A study published in June, funded by the American Chemistry Council, warns of health risks in unwashed reusable bags, citing bacteria found in 84 reusable grocery bags sampled from shoppers in California and Arizona. The study was widely publicized, but a Consumer Reports review of the study criticized the small sample size and said that the kind of bacteria found in the bags didn't normally make people sick. Charles P. Gerba, a professor at the University of Arizona who conducted the original study, says that the presence of any bacteria indicate a health risk, but that washing reusable bags can eliminate the risk.

As states debate bag laws, they'll be keeping an eye on results from the cities that now have some experience with them. Some have criticized San Francisco's outright ban on plastic bags because it seems to have led to an increase in the consumption of paper bags. By contrast, D.C.'s 5-cent tax seems to have changed consumer behavior. According to grocers' estimates cited by the D.C. Department of the Environment, bag consumption has dropped by half since the tax went into effect in January.

It is difficult to gauge the impact on litter and waste. In San Francicso, plastic bags are still reaching the landfill because the ban only applies to chains and large stores. In D.C., the Department of the Environment plans to study litter using a trash trap on a tributary of the Anacostia River. But John Wasiutynski, an environmental specialist with the department, says it's difficult to measure a direct result. "Plastic bags tend to move slowly," he says. "They get caught, snagged in branches. They're clingy but they do eventually migrate out."