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August 18, 2008
Volume 86, Number 33
pp. 72-73

It's In The Bag

The Case Of Paper Versus Plastic

Alex Tullo

MOST PEOPLE HAVE been annoyed by the sight of plastic shopping bags tangled in trees or have had to swerve around one tumbling down the highway. Many cities and towns view the bags as a major culprit of their litter problems. And some jurisdictions are enacting legislation such as recycling mandates and are even taxing or banning bags to get rid of the nuisance.

But the issue isn't so black and white. Plastics proponents say the bags aren't as bad for the environment as they're made out to be. Governments making the "paper versus plastic" choice for consumers, they say, may be enacting counterproductive environmental policy.

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The front line of this battle is an ordinance passed last year in Oakland, Calif. Citing litter, marine pollution, landfill waste, and other problems, Oakland's city council followed the lead of its neighbor San Francisco and banned the use of noncompostable plastic bags in stores that gross more than $1 million annually.

Unlike the San Francisco ban, the Oakland ordinance faced resistance from industry. A group of bag manufacturers and other plastics firms calling themselves the Coalition to Support Plastic Bag Recycling took the City of Oakland to California Superior Court.

In passing the bill, the group claimed, the city ignored the California Environmental Quality Act, which requires governments to evaluate the environmental impact of their activities. If the city did that, the coalition maintained, it would have found that the bill encouraged the use of paper bags and compostable bags. The former generate more greenhouse gases than plastic bags, the coalition said, whereas the compostable plastic bags foul up the recycling of conventional plastic bags.

The court sided with the coalition in its preliminary decision. It found that "substantial evidence in the record supports at least a fair argument that single-use paper bags are more environmentally damaging than single-use plastic bags."

The decision was counterintuitive to people who believe that paper is the right choice. Yet Keith Christman, director of packaging in the plastics division of the American Chemistry Council (ACC), says plastic bags have gotten a bad rap. "Our goal is to educate people about the fact that plastic bags are an environmentally responsible choice," he says.

The right answer to the paper-or-plastic question is plastic, Christman says. For one thing, he notes, paper bags weigh 10 times more than plastic bags. And, he argues, plastic bags generate fewer greenhouse gases over their life span, require less energy and water to manufacture, and generate less waste than paper bags.

Christman cites various life-cycle assessments of shopping bags that consultants and governments have released over the years. In 2007, Boustead Consulting conducted one such study for the Progressive Bag Alliance, an industry group that was folded into ACC as the Progressive Bag Affiliates. According to the study, the manufacturing of 1,000 paper bags, incorporating 30% recycled content, uses 2,622 MJ of energy versus 763 MJ for the production of enough plastic bags to carry an equivalent amount of goods. The paper bags generate 33.9 kg of solid municipal waste versus 7.0 kg for plastic. The paper bags require 1,004 gal of water in their manufacture compared with only 58 gal for plastic bags.

The Boustead study also found that 1,000 paper bags generate twice as much greenhouse gas emissions—some 0.08 tons of CO2 equivalents—in production and after disposal than do plastic bags. This is because plastic bags are thought to sequester CO2 forever, whereas the study assumes some decomposition of the paper in a landfill.

A study conducted by the Australian Department of the Environment & Heritage said manufacturing plastic bags generates about one-half of the greenhouse gas emissions of, and requires less than one-third of the energy used in, paper bag production. Similarly, a study by the South African government noted that manufacture of plastic grocery bags consumes 23% less energy and generates 76% less solid waste than does production of paper bags.

Bryan Early, plastic waste reduction campaign coordinator for Californians Against Waste, supports the plastic bag bans in San Francisco and Oakland. He also supported a proposed law that was recently struck down in California that would have required retailers to meet recycling benchmarks or face a fee on plastic and paper bags.

According to Early, life-cycle assessment studies have ignored other pollution problems. "The main reason we are targeting plastic bags and certain other materials is that they are prone to be littered," he says. "Once they are littered, they end up in the environment. How long they persist, we really don't know."

Early cites a report compiled last year by the staff of the Los Angeles County Board of Supervisors. It said local landfills and waste-transfer stations spend between $1,500 and $25,000 monthly on patrols that pick up plastic bag litter. Los Angeles evaluated the waste in the city's storm drain catch basins and found that 25% of it by mass was plastic bags.

Much of this plastic ends up in the world's oceans. Environmental activists point to the North Pacific Central Gyre, an area in the Pacific Ocean about the size of Texas where ocean debris accumulates. Dubbed the "Great Pacific Garbage Patch," the area is home to six times by weight more plastic particles than zooplankton, according to Long Beach, Calif.-based Algalita Marine Research Foundation.

And plastics can be deadly to marine animals. For instance, environmentalists say, sea turtles eat plastic bags, confusing them for jellyfish.

However much proponents and opponents of plastic bags disagree, they agree on one thing: Reusable bags are probably better than either paper or plastic. "What every study finds is that the clear solution to this problem is reusable bags," Early says.

Even Christman acknowledges that reusable bags are hard to beat. "Intuitively, we know that reusable bags, if people reuse them over and over again, could have some environmental benefits," he says.

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Chemical & Engineering News
ISSN 0009-2347
Copyright © 2009 American Chemical Society

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