The Oromocto Mall has reopened after three people became sick on Tuesday.
Methane gas was detected and recent flooding could be to blame, regional medical officer of health Dr. Na-Koshie Lamptey told CBC News on Wednesday.
The mall closed at about 10:45 a.m. on Wednesday. The ban was lifted around 5:30 p.m.
Mall management say they did not know whether the issue of standing sewage in the basement had been fixed, but the air quality no longer poses a threat to human health.
Lamptey believes the three people who were sick were assessed at hospital and released.