"Since cleaning products aren't food, beverages or drugs meant to be ingested, they aren't regulated, per se, by the U.S. Food and Drug Administration. However, makers are required by the U.S. Environmental Protection Agency (EPA) to list ingredients that are active disinfectants or potentially harmful. Otherwise, they usually keep their other ingredients secret, presumably so competitors can't copy their formulas.
But consumer advocate Sloan Barnett, author of Green Goes with Everything, doesn't give manufacturers the benefit of that doubt. "Call me suspicious, but I honestly don't think it's because the recipe is top secret," she says. "If it was, there wouldn't be so many competing products with identical ingredients." Barnett thinks manufacturers don't want to scare off consumers by disclosing how many potentially harmful chemicals are flying under the EPA's radar in their products."