“Denim is a really dirty business,” says Michael Preysman, founder and CEO of Everlane, an online clothing retailer known for transparency in pricing and manufacturing processes. The dark side of denim manufacturing has been on Preysman’s mind over the last few months. He’s been delving into the global supply chain to find a way to make denim as sustainable as possible. It hasn’t been easy, but after visiting thousands of factories around the world–and stumbling on an enlightened factory owner–Everlane is launching its first-ever line of jeans on September 7. The fashion industry is among the most polluting in the world, but making denim–a $60 billion global market–is particularly terrible for the environment because it pollutes the water. On average, it can take up to 10,000 liters of water to make a single pair of jeans. In most factories, the majority of untreated waste water–full of dyes and other chemicals–goes back into rivers and the ocean. Read more at Fast Company.