Sussex Police is searching for three or four suspects wanted in connection with the theft of six gas cylinders from Royal Sussex County Hospital in Brighton.
Police have released CCTV images of the incident which took place at 2.43am on Tuesday, July 18.
The offenders reportedly used stolen number plates on a red Ford Fiesta to drive into the hospital car park, before they entered a store room and took the items.
Officers are keen to identify the suspects and gather information as police said the bottles may be dangerous if used incorrectly.
Anyone with any information is asked to report it online with the reference 103 of 18/07.
Alternatively, you can visit the Crimestoppers website or contact the independent charity anonymously on 0800 555 111.