From Clinician Reviews:

Recently, a group of health care providers gathered to help Illinois lawmakers collect information for new legislation regarding medical waste. The law, which is now in effect statewide, bans health care institutions from flushing leftover tablets, capsules, and other nonliquid prescription drugs down the toilet. The Illinois legislature passed the law in an effort to prevent pharmaceuticals from polluting the Great Lakes, which are the source of many municipal drinking water supplies. Read more.