How Green Are Your Jeans?
Some 450 million pairs of jeans are sold in the United States each year -- 1.5 pairs for every man, woman, and child. The average woman has eight pairs in her closet. Chances are that to make those jeans, cotton crops were drenched in pesticides; fibers were stained with toxic dyes; and the resulting fabric was sandblasted, chemically softened, and ripped and scrunched to create the wrinkles and tears that make new jeans look perfectly broken in.
There is another option: the eco-minded can invest in a pair of jeans woven from organic cotton, dyed with natural indigo, and faded with nontoxic ozone. These eco-jeans are pricier than the conventional pants peddled at your local superstore (though not necessarily costlier than high-fashion conventional jeans), but how much healthier for the environment are they? A close look at America's favorite apparel reveals some surprising wrinkles.
Cotton is one of the world's thirstiest crops. About 1,500 gallons of water are required to produce the 1.5 pounds of cotton used to make a single pair of jeans, not including the water used to dye and finish the fabric. Let's not forget the insecticides: cotton growers use 25 percent of all such chemicals applied worldwide, including highly toxic organophosphates (chemical relatives of nerve gases used during World War II). Pesticide sprayers and farm equipment run on oil, and about a pound is required to harvest enough cotton for a single pair of jeans.
The makers of some "green" jeans sidestep pesticides and oil-guzzling machinery by opting for hand-picked organic cotton. Because pesticides are not applied to organic cotton, yields can be as much as 50 percent lower than those of conventionally produced cotton, which means more land may be needed to make organic jeans. Some manufacturers also use bamboo. It's a fast-growing, water-efficient crop that can be cultivated without pesticides and fertilizers, but turning it into a comfortable pair of jeans requires some nasty chemical treatments (details below).
Cotton yarn is typically "sized" with starch to increase its strength for weaving, bathed in oil-derived paraffin to smooth and lubricate it, and, in some cases, "mercerized" in caustic soda, which gives it a worn look. Starch biodegrades, but when dumped in waterways the microbes that eat it also consume oxygen. Aquatic life depends on that oxygen, and starch is just one of many chemical treatments, including dyes, that deplete it. Caustic soda, a key ingredient in Drano, can kill aquatic life and burn workers. Bamboo eco-jeans are made by "cooking" shoots in caustic soda before they're turned into fiber.
DYEING 'EM BLUE
To get the right shade of blue, cotton yarns may be dipped a dozen or more times in enormous vats of synthetic indigo, which is often made from coal or oil. Some factories have machines that precisely measure the concentration of dye in solution, enabling a manufacturer to recycle spent liquid by adding just the right amount of fresh dye. But in developing countries, where water and dyes are cheap and environmental regulations lax, factories without modern equipment often dump the old dye into nearby waterways. Water samples taken downstream from textile plants in Tehuacan, Mexico, a major denim-producing region, have been shown to contain lead, mercury, cadmium, and selenium. Local farmers complain of chemically burned seedlings and sterile soil.
Eco-jeans may be dyed with pigment from the Indigofera tinctoria plant, but these natural pigments are found in less than 1 percent of all indigo dyes. Natural or not, indigo pigments don't dissolve in water, so creating a liquid dye requires chemical solvents. The upshot: most eco-jeans are dyed conventionally.
Yes, zippers matter too. Brass is used to fashion the zippers, buttons, and rivets found on jeans, and brass is made from copper and zinc. Extracting and processing these minerals comes with a whole slew of nasty side effects, from acid mine drainage to air pollution laden with toxic metals such as cadmium and lead. Alternatively, some eco-jeans feature hardware made from recycled scrap metal.
"Stone washing" is a euphemism for a number of processes that give denim a worn look. Each pair of jeans is washed and rinsed multiple times, consuming more water and energy at every turn. Denim may be physically sanded or blasted with silica, or dye may be stripped using chemicals such as potassium permanganate, which is highly toxic and contains heavy metals. Various enzymes may also be used; when improperly dumped, they sap oxygen from waterways. Scrubbing jeans releases denim and silica dust, which can inflame workers' lungs and cause silicosis. In a recent study of denim sandblasters in Turkey, more than half of the workers showed signs of the condition; the average worker was 23 years old and had been on the job just 36 months.
To avoid these problems, some eco-brands use ozone to fade denim. Ozone is produced by exposing oxygen to ultraviolet light. It is then dissolved in wash water or mixed with steam and sprayed on denim in a sealed chamber. The ozone breaks down as it reacts with the fabric.
THE RIGHT FIT
If you were hoping to save the world by the seat of your pants, think again. Organic cotton jeans are a good first step, but few are processed in a planet-lite manner. The evolution of jeans from durable work wear to fashion statement came at a heavy cost: each new shade of blue, each stone wash and slick finish, requires yet another rinse cycle-and more energy and water.
Linda Loudermilk jeans are as eco-friendly as they come, but they can run you a couple hundred dollars, well out of range for most of us. Levi's eco-jeans are more affordable, starting at around $60. Although they feature organic cotton and recycled hardware, they're dyed conventionally. However, the industry shows signs of change. Levi's, the Gap, and Wal-Mart are among the major companies now working with environmental groups, including the Natural Resources Defense Council, to green their supply chains all the way down to dye selection. Chemists know certain dyes suck up more oxygen than others, but it's a long way from the lab to the dye house. With more information, designers will be able to specify low-impact colors and finishes. Of course, the lowest-impact jeans are those you already own (washed in cold water and air-dried). Green or not, shipping new jeans halfway around the world has a hefty carbon footprint. If you must buy new ones, do your homework: visit manufacturers' Web sites before you buy.
Photograph by Jens Mortensen