View Comments People could be unknowingly spreading "forever chemicals" on their lawns and gardens in the form of fertilizers sold across the country, including Milwaukee's famed Milorganite. A study by the Sierra Club and the Michigan-based Ecology Center found that Milorganite was one of several fertilizers that contain PFAS. All of the fertilizers are made of at least 50% biosolids — treated sewage sludge — rich in nutrients helpful in growing grass, fruits and vegetables. MMSD has been selling Milorganite as a commercial fertilizer since 1926 in the United States and Canada, and on its website touts the product as "one of the nation's oldest recycling efforts."