The quality of her performances became increasingly inconsistent. There were persistent rumors of her drug addiction and her life was "a real earthquake" according to statements of close friends, although Fred Weinberg, who engineered, and also produced a vast amount of her albums, stated that "In all the years I worked with Lupe, not once did I ever see her on drugs, or using drugs...Heck, she never even drank liquor due to her strong belief in religion." She ended some of her on-stage engagements being treated with an oxygen mask. Although she may have been poorly managed by her label Fania Records in particular, she managed and produced herself in mid-career, after she parted ways with Tito Puente. However, in the late 1960s her ephemeral career went downhill. The explosion of salsa and the arrival of Celia Cruz to New York were the determining factors that sent her into the background and her career declined thereafter.