In 2004, 98.4 percent of all shoes purchased in the US were imported from a factory in another country. Imported shoes totaled over 2 million pairs. This means that over 98 percent of shoes have criss-crossed the globe to reach this country via a transport system that uses nonrenewable fossil fuels and generates greenhouse gases. Also, US shoes contribute to significant additions to landfills. In 2005, Americans generated some 8 million tons of waste from footwear and clothing in 2005—approximately 54 pounds per person.
Downsides of conventional shoe construction
Over half of the leather tanned around the world is used for shoe-making, and the leather tanning process impacts the environment by releasing toxic substances. In 2001, the top countries for leather production respectively were China, Italy, India, Korea, and the US. China and India accounted for over half of the leather produced and have relaxed or non-existent environmental regulations, which results in tanneries releasing more of these toxic substances into the environment.
Additionally, some shoes made of synthetic materials contain PVC (polyvinyl chloride), a hazardous plastic. Dioxins are released both when PVC is manufactured as well as when it is incinerated. Dioxins can contaminate both air and water. Although the main source of dioxins in the environment is now uncontrolled backyard barrel burning rather than industry (thanks to tighter regulations), the incineration of shoes and other products in landfills still has an impact on dioxins released into the environment. Industrial plants that produce the chemicals used to make PVC also continue to be a source of dioxins in the environment.
Changes in the footwear industry
New innovations and practices in the footwear industry include the use of hemp, one of the most environmentally friendly fibers in the world. Other changes in materials include swapping traditional toxic solvents for water-based adhesives, using organic cotton and vegetable-based dyes, as well as making shoes from recycled materials like magazines, polyurethane, soda bottles, cardboard, and post-consumer tire rubber.
Related health issues
The process used to tan leather has long been noxious and polluting. Pollution from tanneries includes mineral salts such as aluminum, iron, and zirconium, as well as formaldehyde and coal-tar derivatives. Certain oils and dyes used in the tanning process are cyanide-based. Similar to the rest of the world, more than 95 percent of American-made leather is chrome-tanned. The production of chrome-tanned leather contributes waste to the environment, including chromium, classified as a hazardous material by the US Environmental Protection Agency (EPA). Chromium released from tanneries can contaminate drinking water and is dangerous to ecosystems as well as humans. Tanneries also produce other pollutants, including protein, salt, hair, lime sludge, sulfides, and acids.
One material used for foam padding in shoes, polyurethane, is also of concern. Polyurethane foam often contains flame-retardant chemicals called penta-BDEs. Studies show levels of these chemicals are rising in human breast milk. The long-term effects on humans are unclear, but research performed on animals reveals that penta-BDEs can damage the liver, cause harm to developing brains, and lower production of the thyroid hormone.
Shoes produced using solvent-based adhesives contain volatile organic compounds (VOCs), such as urethane. These VOCs produce hazardous waste that may be carcinogenic to humans. Water-based adhesives are an alternative for gluing the midsole to the outsole of shoes without using chemicals.
Further, industrial solvents and glues used in shoe production can harm employees in shoe factories. Specifically, toluene, a solvent that has been found in the air of Vietnamese shoe factories, can cause irritation to the eyes, skin, and respiratory system. Extended exposure not only harms developing fetuses, but it can also lead to liver, kidney, and central nervous system damage.
- dioxins: Chemicals produced in industrial processes, most often combustion. They contain chlorine that can harm humans, usually ingested through food grown in soil where dioxins have accumulated.
- volatile organic compounds (VOCs): Organic solvents that easily evaporate into the air. VOCs are emitted by thousands of products, including paints, cleaning supplies, pesticides, building materials, and furnishings, and may cause immediate and long-term health problems. VOCs are also considered a possible carcinogen, and can create ground-level ozone, the main component of smog.