Nedda Casei, who in the 1960s and ’70s could be reliably heard as Suzuki, Maddalena, Lola and other bread-and-butter mezzo-soprano characters at the Metropolitan Opera before transforming herself into a pathbreaking labor leader, died on Jan. 20 in hospice care in Manhattan. She was 87.

A niece, Janice Arponen, said the cause was a stroke. Ms. Casei sang in some 280 performances at the Met, from her debut as Maddalena in Verdi’s “Rigoletto” in 1964 until her final curtain, in 1984, as Larina in Tchaikovsky’s “Eugene Onegin.” She also sang “Carmen” there. In one performance, in 1978, as the understudy for Elena Obraztsova, she had to go on at the last minute.