MODIFICATIONS are being made this week to the Goonellabah Sports and Aquatic Centre in an attempt to address poor air quality issues.
In June, eight staff at the complex were injured and one person was hospitalised after workers complained of skin and respiratory irritations.
"They were treated for chlorine inhalation and we haven't been able to determine exactly what caused that, but we have made changes to the air quality system to eliminate the issue in the future completely," Lismore City Council general manager Gary Murphy said.
When a suspected mechanical failure was identified on June 19, Mr Murphy said the pool was closed and Workcover launched an investigation.
"There may have been some issues that the plant room air was actually being vented into the pool hall, but now with the changes being made, that possibility will be eliminated completely," he said.
"We have got workmen on site this week trying to address the air intake at GSAC and making some changes there."
Mr Murphy said the exact cause of the poor air quality was still unknown, after water and air quality testing had been done.
"We had a firm from Brisbane down who did all sorts of monitoring and air quality testing to try and make sure they were covering all the bases," he said.
"What the guys are working on now is installing internal air intake vents for the pool ventilation system just to make sure we are getting fresh outside air and are not going to have any poor air quality issues in the future."
GSAC reopened on June 26, after Workcover deemed it was safe to do so with all doors and windows open to ensure adequate ventilation.
Meanwhile, 1200 kids enrolled in the learn to swim program haven't had any lessons this semester.
A council statement issued on July 4 stated "Swimming lessons have been cancelled due to the increased cold air flow through the facility and parents have been notified."