Polylactic acid (PLA) biopolymer is undergoing criticism for not being compostable or recyclable by consumers. Recycling advocates are concerned that retail PLA water bottles will most likely contaminate recyclables, especially in states where recycling rates are high. Natureworks says that given the small amounts of PLA being used in packaging, contamination is not likely. A 2006 study commissioned by the company showed recycling, not composting, as the greenest way to deal with PLA. For everything but water pollution, it said that PLA retains environmental advantages over conventional plastics, even if it isn’t recycled.