Are the materials used in athletic shoes environmentally harmful?

From the Editors of E/The Environmental Magazine

Are the materials used in athletic shoes environmentally harmful?

—Margaret Southgate, Hamilton, New Zealand

The ingredient that gives some athletic shoes their cushioning support is sulfur hexafluoride, known as SF6. It’s a popular man-made gas with a uniquely buoyant chemical structure. Unfortunately, SF6 is also an unusually persistent global warming gas that is more damaging to the atmosphere (molecule by molecule) than carbon dioxide.

Nike”s “Air” technology previously used 288 tons of SF6 a year, accounting for one percent of worldwide production before they began to phase out SF6 use in the mid 1990s. According to a spokesperson from the Nike Environmental Action Team, upon the company”s discovery in 1992 that SF6 was environmentally damaging, they began investigating alternative materials and started to replace SF6 air bags with nitrogen bags. In October of 2001, Nike partnered with the Center for Energy & Climate Solutions and the World Wildlife Fund, making a commitment to complete the phase out of SF6 by June of 2003. “We”re still on an aggressive plan to transition SF6 to more environmentally friendly substances, and most of the transition has happened, but we”ve run into complications in some of our newer and more technical products in terms of finding a suitable substitute,” according to Veda Manager, director of global issues management at Nike. He says the company”s new goal is to end SF6 use by 2006.

There are other environmental issues with shoes, when you consider the resources and energy that go into making our feet comfortable. Perhaps in exchange for its overuse of SF6, Nike is making an attempt to reduce running shoe waste. They now will take back their shoes, as well as other brands, grind them up and reuse them in athletic surfaces. Granulated rubber from the shoe outsole can be turned into artificial soccer, football and baseball field surface, and weight room flooring. Granulated foam from shoe midsoles can become synthetic basketball courts, tennis courts and playground surfacing tiles. And fabric from the shoe uppers can be used for padding under hardwood basketball floors. Since 1993, Nike has recycled 13 million pairs of shoes.

CONTACT: Nike Environmental Action Team, 9000 SW Nimbus Drive, Beaverton, OR 97007, (503) 671-8044,; Center for Energy & Climate Solutions, 2900 S. Quincy Street, Suite 410, Arlington, VA 22206, (703) 379-2713,