The Georgia Environmental Protection Division said Wednesday a recent fish kill on the Ogeechee River in Southeast Georgia likely was caused by the drought conditions of low stream flow levels and high water temperatures. But an "exact cause will never be known," said the agency, following a 2-week investigation.

All of the approximately 100 dead fish found were downstream of the discharge pipe of the King America Finishing Plant near Statesboro. Last year, about 38,000 fish died along a stretch of 70 miles downstream of the company's discharge.

An EPD and U.S. Environmental Protection Agency investigation concluded last year that kill was  caused by a combination of low river levels, high temperatures, and pollutants that so weakened fish they died of the bacterial disease columnaris. The investigation did not connect the kill to the KAF discharge.

But, last January, in a letter to Ga. State Senator Jack Hill (R-4th District), EPD director Judson Turner wrote that EPD had "traced the problem to King America Finishing," which for years had been discharging wastewater from its fire-retardant fabric production line without a permit.

In September of 2011, EPD and KAF signed a consent order imposing a $1 million penalty on the company, and requiring it to improve its discharge and increase the it's self-monitoring of its discharge.

The EPD said in a press release Wednesday water samples taken and analyzed since the recent kill "show the river is meeting water quality standards." EPD said the fish died from columnaris and aeromonus bacteria. "Environmental stressors, such as high temperatures and low water flow, make fish more susceptible to disease," said the EPD.

Flow in the Ogeechee River dropped to 60-70 cubic feet per second in May.  The historical average stream flow needed to support healthy fish is 127 cubic feet per second, said EPD. Water temperatures also have risen above 80 degrees Fahrenheit, which contributes to health problems with fish, according to the agency.

Following the recent fish kill, EPD took water samples on May 24 from the river at Rocky Ford, the King America Finishing plant, U.S. highway 301, route 24, route 204 and U.S. highway 17. Lab tests were conducted for ammonia, dissolved oxygen, biological oxygen demand, chemical oxygen demand, color, conductivity, formaldehyde, pH, metals including sodium and chromium, sulfide, Total Recoverable Phenolics, Total Suspended Solids, Total Kjehldahl nitrogen, Total Phosphorus, Nitrate/Nitrite, hardness, turbidity and total coliform.

EPD also conducted an extensive inspection of the King America Finishing facility in late May. That included analysis of discharge monitoring reports, inspecting production and wastewater treatment operations and water sampling at the plant’s discharge point in the river. EPD determined the plant is operating in compliance with current requirements.

Effingham, Bulloch and Bryan counties on Wednesday lifted their advisory to stay out of the river. The EPD is holding a public hearing June 12 on issuing King America Finishing a permit to discharge into the Ogeechee from its fire retardant fabric production line.