Here is a description of the each of the materials we've selected as part of our eco-sensitive product offerings, along with information about the benefits and drawbacks from well-regarded sources.

Bamboo Fabric
Bamboo fabric is a natural, soft textile made from the pulp of the bamboo grass. Highly absorbent, hypoallergenic, fast drying and breathable, it is an ideal wicking fabric for next-to-skin use. Its ability to insulate keeps the wearer cooler in summer and warmer in winter. The bamboo plant has antibacterial properties that transfer into the fabric and remain through several washings.
Pros: Bamboo grows very rapidly and replenishes itself each year. Additionally, the plant can be harvested without ecologically damaging chemicals, and chemicals are not needed to turn the plant into fiber. The process of making unbleached bamboo fabric is light on chemicals.
Cons: Bamboo fabric is still expensive to manufacture. It's also not grown in large quantities in the United States. The fibers often need to be bleached before dyeing.

Organic Cotton
Non-organic cotton is one of the most heavily chemically treated crops in the world. Although it comprises less than three percent of the world's agriculture, it uses 25 percent of the chemical pesticides produced annually.
Pros: Organic cotton is renewable, biodegradable and non-toxic. The material is traceable through the supply chain.
Cons: Organic cotton is more expensive to produce than traditional cotton and has limited sources. Organic cotton clothing labeling can be confusing to the consumer. For example, "100 percent organic" means the garment is sewn with organic cotton thread and 100 percent organically produced fabric. "Organic" means 95 percent of the content is organically produced cotton. "Made with organic cotton" means that 75 percent of the content is organically produced cotton.

Organic Wool
For wool to be certified organic, several federal standards must be met in the production process. The sheep or goats may not be given synthetic hormones or insecticidal treatments and they must be given certified organic feed. The land used to raise the animals must follow strict guidelines: no synthetic pesticides may be used on grazing land and the number of grazing animals must stay within that land's carrying capacity.
Pros: Organic wool is renewable, biodegradable and supports more sustainable farming.
Cons: Organic wool is more expensive to produce than conventional wool. Limited sources currently exist for organic wool production.

Hemp
The production of hemp fabric is one of the oldest industries on the planet. With the appearance of linen and the soft hand of flannel, hemp is a very desirable fabric for sportswear and casual wear. While industrial hemp has no illicit uses, the production of hemp is illegal in the United States. Fabric made from hemp is warm, absorbent, breathable and significantly more durable than cotton fabric.
Pros: Hemp is a fast-growing, economical renewable resource-only 100-120 days from planting to harvest. Hemp is most often grown without herbicides, pesticides and fungicides, and is a natural weed suppressor due to the fast growth of the canopy.
Cons: Hemp cannot be grown commercially in the United States. There is no internationally recognized certification for hemp, but the Hemp Industries Association has developed standards for hemp content in fabric and clothing.

PLA
Polylactic acid, or PLA, is a biodegradable and recyclable polymer derived from 100 percent renewable resources that are starch-rich, such as corn. PLA exhibits many properties that are equal to or better than many petroleum-based plastics, which makes it suitable for a variety of applications.
Pros: Starch-rich products are renewable resources. PLA is recyclable and will biodegrade down to carbon dioxide and water in commercial composting systems.
Cons: Because of the relatively small manufacturing volume, PLA is still expensive to produce and is impacted by fuel and corn commodity prices. Although fossil fuels are not used in the polymer itself, they are still needed to power the processes involved in harvesting of corn and chemical production. Lastly, the U.S. commercial corn market has a significant percentage of grain that comes from corn plants that have been genetically modified to improve production. As a result, as with many other products that use commercially available corn, PLA production currently supports the market for genetically modified crops.

Recycled PET
Polyethylene terephthalate (PET) is one of the most important thermoplastic polyesters. The majority of PET is made into fibers for clothing, while 30 percent is used for bottles and containers. It is also a material that can be reclaimed and readily recycled-for example, "pop bottle fleece" has existed for many years.
Pros: The use of recycled PET reduces landfill waste, the use of raw materials such as petroleum and the use of energy in the manufacturing process. "Disposable" PET bottles represent an increasing problem as the market for bottled water has skyrocketed. Finding a recycling solution that can reduce this waste stream would be a big environmental win.
Cons: Contamination through manufacturing or consumer use makes post- consumer recycled PET very difficult to use as new fibers and fabrics because it is not as high a quality and has different properties-a less soft feel, for example. For this reason, the plastic is often collected and used in bulk applications where the material purity is not important (i.e, park benches). While better than the landfill, this "down cycling" approach has limited markets.

REI and other outdoor brands are working with fiber and fabric suppliers using new processes which can restore the recycled material to its original quality. However, these techniques are in relatively low production and are currently expensive.

Post-Industrial Recycled Polyester from Polartec® (formerly Malden Mills)
Polartec® is moving toward recycled PET by reusing scraps and by-products of fabric and yarn manufacturing-post-industrial waste. REI supports this effort as a transitioning from virgin polyester to the use of recycled materials by using Polartec recycled fabric as an eco-sensitive choice.
Pros: The reuse of manufacturing scraps reduces waste and the amount of virgin petroleum products needed. It also reduces the energy used in processing. The development of manufacturing capabilities to reprocess the material into high quality fiber and fabric is intended to be a first step in using increased post consumer waste.
Cons: Generally, recycling industrial waste is viewed as a process improvement rather than a major environmental win. Achieving a process that utilizes a high percentage of post consumer waste will be the ultimate goal.