Berkeley — As part of its "Zero Waste" campaign, the three farmers markets in Berkeley will be eliminating all plastic bags and packaging from their weekly events, making Berkeley the first city in the nation to do so, organizers said.

The goal of the campaign is to remove, reduce and recycle plastic, and to recycle and compost all materials generated at the markets. The markets encourage shoppers to bring their own cloth bags and previously used paper and plastic bags.

Organizers say single-use high-density polyethylene bags pose significant problems to the environment, wildlife, and human health through their production, use, and disposal. They can take from 400 to 1,000 years to break down, and their constituent chemicals remain in the environment long after that, market organizers said.

Market organizers said Berkeley farmers markets are now designated Zero Waste Zones in which customers and vendors are expected to make every effort to eliminate waste to landfills. Vendors selling prepared foods will be required to use compostable packaging and utensils. In addition, vendors can purchase compostable bags, made from renewable resources, to have available for shoppers for a small charge.

Other farmers markets are also getting rid of plastic bags and packaging. The Boulder, Colo., farmers market was the first in the nation to reduce the use of plastic bags and packaging. The Monterey and Irvine farmers Markets have phased out plastic bags, but not plastic packaging. The Santa Monica farmers markets are working to phase out the use of plastic bags and require all prepared food vendors to use packaging which is compostable or recyclable.

In conjunction with Berkeley's Earth Day celebration, the April 25 market will hold a special Zero Waste Event from 10 a.m. to 3 p.m. at the market on Center Street at Martin Luther King Jr. Way.

There will be Earth-friendly carnival games, a bag-making workshop to learn how to make reusable bags, and a drawing to win Zero Waste Kits, which include cloth bags, a stainless steel water bottle, a reusable takeout container, market gift certificates and more. There also will be demonstrations of biodiesel and electric cars and solar power, a climbing wall, craft and community booths, and entertainment.

The Berkeley farmers markets are held from 10 a.m. to 3 p.m. Saturdays at Center Street and Martin Luther King Jr. Way; from 2 to 7 p.m. Tuesdays at Derby Street and Martin Luther King Jr. Way; and from 3 to 7 p.m. Thursdays at Shattuck Avenue and Rose Street.