A city public works official said problems at the Moccasin Bend Treatment Plant on March 15 and 16 were set off due to "human error."
Justin Holland, deputy public works administrator, told the City Council that a chlorine leak was caused when an employee was changing a chlorine cylinder and accidentally released a valve that released chlorine gas.
He said the employee was wearing full safety garb.
However, he said an unprotected employee outside the building inhaled chlorine gas through an exhaust fan. He was treated at a local hospital.
Mr. Holland said scrubbers "did their job" by neutralizing the leak.
However, he said two fires on March 16 resulted from mechanical problems with the scrubbers.
Mr. Holland said steps are being taken to assure that the same problem cannot occur again and that workers near the building are protected.