Checkout bags of the kind you get at grocery stores, whether paper or plastic, are an environmental pariah. While paper bags may be readily recycled, their impact on the boreal forests is far from sustainable.
And plastic bags are nothing but trouble over their entire life cycle. They're a source of greenhouse gas emissions in their manufacture; they're extremely difficult to recycle (if you can even find a market for the material), and they're among the most common items littering our city streets, highways and oceans.
At the end of 2004, San Francisco's Environment Commission focused on the checkout bag problem and floated the idea of charging a fee for each bag.
Our state laws require that fees reflect real costs - we cannot levy punitive fees. The checkout bag fee was intended to recoup costs the city currently pays for bag-related problems, from litter on the streets to contamination of recyclables.
A similar measure in Ireland reduced the number of checkout bags by over 90 percent within one year, but here in the United States politics are a bit different.
We faced opposition from the grocery and plastics industry. The fee was assailed as a regressive tax, unduly burdensome to the poor, and while we did get support from our local Sierra Club chapter and the Natural Resources Defense Council, some residents complained bitterly about having to pay for what once was free.
Rather than succumb to the political winds and drop the issue entirely, San Francisco Mayor Gavin Newsom's office worked with Supervisor Ross Mirkarimi and with industry groups to see if a voluntary reduction program could deliver significant reductions.
As a result, San Francisco entered an agreement with city grocery stores to reduce 10 million checkout bags by the end of 2006.
Additionally, the Progressive Bag Alliance, an industry group that represents plastic bag manufacturers, is mounting a public service ad campaign to encourage customers to ask for fewer bags, reuse them, and ultimately recycle them at an in-store recycling collection center.
A reduction of 10 million bags will keep 95 tons of plastic material out of San Francisco's waste stream and will reduce San Francisco's contribution of greenhouse gas emissions by nearly 1 million pounds of carbon dioxide.
This is equivalent to 44,000 gallons of oil, or taking more than 14,000 automobiles off the road for a day.
We certainly hope our industry partners make their goals and set even more aggressive reduction targets in the years to come.
Blumenfeld is director of San Francisco's Department of the Environment.