Operating theatres at Scarborough Hospital will be closed for repairs after the discovery of potentially unsafe Raac concrete.
The hospital trust revealed problems with reinforced autoclaved aerated concrete in three of the 29 operating rooms following a Freedom of Information (FOI) request, according to the Local Democracy Reporting Service.
Raac, which was widely used as a building material from the 1950s to the 1980s, tends to crumble over time.
A spokesperson for the York and Scarborough Teaching Hospitals NHS Foundation Trust said the operating theatres had been "assessed as safe" and that the Raac would be removed "in due course via a systematic plan, one theatre at a time".
They said: "There will be no patient impact and no staff will be moved."
Earlier this year planks were found in the roof of the pathology unit at Scarborough Hospital, forcing staff to be moved to temporary workspaces.
Scalby School in Scarborough is among hundreds across the country where similar issues have been identified.