SUMATRA, Indonesia (AP) — With his hand clamped tightly over her mouth, she could not scream, the 16-year-old girl recalls – and no one was around to hear her anyway. She describes how her boss raped her amid the tall trees on an Indonesian palm oil plantation that feeds into some of the world's best-known cosmetic brands. He then put an ax to her throat and warned her: Do not tell.

At another plantation, a woman named Ola complains of fevers, coughing and nose bleeds after years of spraying dangerous pesticides with no protective gear. Making just $2 a day, with no health benefits, she can't...