Merseyside Fire and Rescue Service is currently in attendance at an incident at the Royal Liverpool Hospital.
Crews were alerted at 7.14pm following reports of a gas leak and three fire engines arrived on scene shortly after.
The building has been evacuated as a precaution and firefighters are working closely with hospital staff and partners to investigate the scene.
The incident is ongoing.
Update - 10:20pm
The incident has now been confirmed as a chemical leak in the Clinical Science and Support Building.
Firefighters are working to close the containers and ventilate the affected compartment.
Update - 7:45am:
By 11.26pm the building had returned to safe working levels. Fire crews remained on scene temporarily to check all floors.
Prior to leaving, one crew attended a bin fire at the entrance of the A&E department. One hose reel jet was used to extinguish the fire.
The crew left the scene at 12.30am.