FIREFIGHTERS and police officers attended Nuffield Orthopaedic Centre in Oxford after chemical fumes overwhelmed staff members at its hydrotherapy pool.
Two people are being treated after inhaling the fumes.
Martin Crabtree, spokesman for Oxfordshire Fire and Rescue Service, said: "We believe the material to be chlorine and are monitoring accordingly."
A statement released by the hospital said: "Fire and rescue, ambulance and police teams have attended the Nuffield Orthopaedic Centre following an incident involving chemicals at the hospital’s hydrotherapy pool.
"Two members of staff are being assessed at the scene after inhaling fumes. We would like to reassure patients and staff that the situation is being handled by the Fire Service and there is no danger to the public.
"The main entrance off Windmill Road to the hospital site has been closed as a precaution. Patients can still access the hospital site via the Old Road entrance. Patient appointments are going ahead as scheduled."
South Central Ambulance Service NHS Foundation Trust spokesman David Gallagher said: "We were called to the Nuffield earlier this afternoon, 13.20, after two Estates workers, who were mixing chemicals used to clean the centre’s swimming pool, were exposed to a chlorine type gas, resulting in them having symptoms such as runny eyes, sore throats, etc.
"We sent an officer and an ambulance to the scene and they were treated at the scene by our staff.
"The incident occurred in an area not accessible to patients so no patients or members of the public were exposed and Thames Valley Police and the Fire Service also attended."
A spokesperson previously said the situation was 'under control'.
Stagecoach buses were not running to or from the hospital after the incident but resumed three hours later.
SERVICE INFORMATION, 700/900. Due to incident we cannot service into Nuffield Hospital in either direction.— Stagecoach Oxford (@Stagecoach_Ox) February 16, 2017