David Hudnall and his son, David Hudnall Jr. (Credit: Pamela D’Angelo)

Unless you’re a farmer or an avid gardener, you probably don’t know much about fertilizers. You put some down and your lawn gets greener and your tomatoes bigger. For people living next door to a farm field, fertilizers have become a worry as some farmers use treated human waste to enrich their soil. Pamela D’Angelo reports.