When a typical laundry detergent washes down the drain, it carries chemicals such as 1,4-dioxane, a likely carcinogen that can’t be removed by standard water treatment plants and that can end up in drinking water. Other common ingredients, such as the somewhat unpronounceable methylisothiazolinone or benzisothiazolinone, can harm the environment. These chemicals have various purposes; methylisothiazolinone is a preservative, for example. Dioxane isn’t used in detergent intentionally but is a by-product of another process. A biotech startup called Dirty Labs is taking on the challenge of cleaning up such cleaning products.

“Everyone has to do laundry, so the scale is pretty mind-boggling,” says David Watkins, CEO and cofounder of Dirty Labs. Americans collectively do an estimated 35 billion loads of laundry in a year. “That’s a whole lot of detergent going down the drain,” he says. “I think that as a consumer, you put your laundry detergent in the washing machine, it washes your clothes, and then it’s gone, and it’s something that’s not very visible to people. But when you start to address the big picture here, all of these chemicals are going into our wastewater system. . . . There is a big accumulation of these things in the environment.”

The startup’s first detergent comes in an ultra-concentrated form (two teaspoons of the product does a load, at a cost of 25 cents per load) and is designed to work in cold water—another way to do laundry more sustainably, since around 90% of the energy used by laundry machines goes to heat up the water. According to research from the American Cleaning Institute, based on Energy Star data, washing four out of every five loads of laundry in cold water would save a household 864 pounds of carbon emissions each year.