OSLO—Oslo's funeral director has long wrestled with the particularly morbid job of dealing with Norway's longtime insistence on "plastic graves." Now, she is using technology to fight back.

Shortly after World War II, Norwegians began a three-decade-long practice of wrapping their dead in plastic before laying them to rest in wooden caskets, believing the practice was more sanitary. Hundreds of thousands of burials later, gravediggers realized the airtight conditions kept...