Wikipedia: When Ebsen turned down studio head Louis B. Mayer’s offer of an exclusive contract with MGM, Mayer warned him that he would never get a job in Hollywood again. However, despite this dispute, MGM did cast Ebsen as the Scarecrow in its 1939 film The Wizard of Oz. Ebsen then swapped roles with actor Ray Bolger, who was originally cast as the Tin Man. Ebsen recorded all his songs as Tin Man, went through all the rehearsals, and started filming. However, Ebsen soon began experiencing cramps and shortness of breath, eventually leading to hospitalization. Doctors determined that Ebsen was suffering an allergic reaction to the aluminum dust used in the Tin Man makeup; Ebsen was forced to leave the production for health reasons. In an interview included on the 2005 DVD release of The Wizard of Oz, Ebsen recalled that the studio heads did not believe he was sick until someone tried to order him back to the set and was intercepted by an angry nurse. Ebsen was replaced by Jack Haley, with the makeup quickly changed to a paste. As noted in a documentary on the 2005 DVD, MGM did not publicize the reason for Ebsen’s departure; even Haley was not told until later. Although Haley re-recorded most of Ebsen’s vocals, Ebsen’s Midwestern voice (as opposed to Haley’s Bostonian accent), with the enunciated “r” in the word “wizard”, can still be heard on the soundtrack during several reprises of the song “We’re Off to See the Wizard.” Ebsen’s recording of the Tin Man’s only solo song, “If I Only Had a Heart,” still exists and is included on the 2-CD Deluxe Edition of the film’s soundtrack, while a still photo recreation of the sequence featuring shots of Ebsen as the Tin Man was included as an extra with all VHS and DVD releases of the film since 1989. Until his dying day, Ebsen complained of lung issues from involvement in “that damned movie.” Ironically, Ebsen outlived all of the major cast members of The Wizard of Oz by at least 16 years, and lived at least 10 years longer than any of them.
Audition photographs of Buddy Ebsen as The Tin Man:
Fan edit including Buddy Ebsen singing “If I Only Had A Heart”: