EMPORIA, Kan. (AP) — Lyon County authorities are investigating to determine the source of a substance that leaked into the Cottonwood River over the weekend. Authorities at first believed the substance discovered in the river Sunday afternoon was some type of oil but later determined it was a naturally-occurring substance that was not hazardous or toxic. Lyon County officials say the river water quality was not damaged. Hazardous waste teams from Emporia and Topeka, as well as several county, state and federal agencies, responded to the spill or were involved in testing the material. KVOE reports the exact material involved has not been determined. Officials also don't know where it originated. The Emporia water department confirmed the water is safe for drinking and all uses.