Health chiefs have confirmed Perth Royal Infirmary is back to normal following a chemical leak alert on Monday afternoon.
Explosive chlorine dioxide gas was found escaping from a canister in a boiler room near the hospital’s stroke unit.
Nine people, including eight members of staff and one visitor, were treated for exposure to the hazardous gas, while emergency crews from across the region arrived to secure the area.
After some discussion with medical staff, it was decided an evacuation was not required.
An NHS Tayside spokeswoman said: “We will carry out an incident review in line with normal procedures.”