76 employees, most in their 20s and 30s, died of illnesses such as leukemia and lymphoma

As a high school senior, Hwang Yu-mi went to work bathing silicon wafers in chemicals at a Samsung factory that makes computer chips for laptops and other devices. Four years later, she died of leukemia. She was 22.

After Yu-mi's death in 2007, her father, Hwang Sang-gi, learned a 30-year-old worker at the same semiconductor line also had died of leukemia. Convinced they died because of their work, the taxi driver launched a movement demanding the government investigate health risks at Samsung Electronics Co factories.