Consumers would increase sustainable apparel purchasing if only they could find it, according to a survey by Ryan Partnership Chicago and Mambo Sprouts Marketing.

Some 69 percent of consumers considered sustainability at least sometimes when purchasing clothing in 2011 and shoppers intend to double their eco-apparel purchases this year, according to the 2012 Styling Sustainability survey.

But access to green apparel is hampering take-up. A third of consumers who don’t regularly consider sustainability in their apparel purchases said sustainable clothing wasn’t available where they shop. About one in four said they didn’t even know where to purchase sustainable clothing, according to the survey.

When shoppers do buy sustainable clothing, 57 percent said they became aware of eco-attributes through product tags, while 37 percent credited in-store information. Some 61 percent of shoppers expressed interest in an apparel sustainability rating or index.

The Sustainable Apparel Coalition is expecting a mid-year launch for its 2012 Apparel Index – a rating tool designed to help companies understand what’s being used to make their products and the impact of apparel supply chains.

Nike, Target, JC Penney and Levi’s are among the team of nearly 30 manufacturers and retailers that helped create “Version 1.0” of the index, launched in 2011.