Firefighter Stephen Hunt got into difficulty inside the building at around 8.35pm, along with another firefighter, Greater Manchester Fire and Rescue Service said.
Both were pulled out by their colleagues and treated by the Ambulance Service before being taken to hospital.
More top news
The number of children in care has increased to its highest level for nearly 25 years, the Government's spending watchdog has said.
Abuse victims are being put through "torture" by the pace at which the Government's inquiry into abuse is progressing, an MP has said.
The number of diabetic and severely overweight patients having weight loss surgery needs to triple to help the future of the NHS, Nice said.