Three years after The Timberland Company started rating the environmental impact of some of its products, company said Wednesday it plans to expand its "Green Index" to all its footwear by 2012.

The company's index rates the greenhouse gas emissions generated during a shoe's production, the hazardous chemicals used and the percentage of recycled, organic and renewable materials in each shoe. The information is used by designers, and tags on the footwear show consumers how the product measures up in each category.

Timberland also is working with the Outdoor Industry Association and more than 200 other businesses on an industrywide Eco Index that would initially be used internally by manufacturers to help designers make more eco-friendly choices, with the eventual goal of giving shoppers a way to compare different brands.

"Individual efforts, like Timberland's Green Index, are good options for now, but to truly empower consumers, we knew we needed a commitment from the entire industry," said Betsy Blaisdell, senior manager of environmental stewardship for Timberland, based in Stratham.

Similarly, Nike has its own internal software tool to evaluate the environmental footprint of its products that it plans to make available to the rest of the apparel industry in the next six months or so, spokeswoman Kate Meyers said.

Nike's "Considered Index" doesn't measure or score the entire supply chain and is not visible to consumers. Rather, it is a tool for designers looking to make sustainable choices right from the start, rather than scoring a product at the end for consumers, Meyers said.

The idea of open-sourcing green information isn't limited to footwear. In January, Nike and nine other companies, including Best Buy and Yahoo!, created the GreenXchange to allow companies to work together and share patents and other intellectual property focused on innovation and business models that have the environment in mind.