SEOUL, Korea, Republic Of -- 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. She died of leukemia four years later. 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. The taxi driver launched a movement demanding the government investigate health risks at Samsung Electronics Co. factories. When Hwang sued after his first claim for government compensation was denied, he struggled to get details about the factory environment because Samsung did not release that information to worker-safety officials.

In this Oct. 23, 2015 photo, Hwang Sang-gi, a founding member of advocacy group Banolim, holds a picture of his daughter Yu-mi during an interview denouncing Samsung's response in its latest negotiations with sick workers outside Samsung buildings in Seoul, South Korea. (AP Photo/Ahn Young-joon) An Associated Press investigation has found South Korean authorities have repeatedly withheld from workers and their bereaved families crucial information about chemicals they were exposed to at Samsung's computer chip and liquid crystal display factories. Sick workers need access to such data through the government or the courts to apply for workers' compensation from the state. Without it, government officials commonly reject their cases. In at least six cases involving 10 workers, the justification for withholding the information was trade secrets. South Korean law bars government agencies from withholding public health and safety-related information because of trade-secrets concerns, but there are no penalties for violations. "In a situation where people's lives are at stake, (Samsung) brought uninformed kids from the countryside and acted like money is everything, using them as if they were disposable cups.'' — PARK MIN-SOOK, 43, a former Samsung chip worker and breast cancer survivor. ​ Samsung no longer omits lists of chemicals used on production lines from reports on workplace safety, as it did in Hwang Yu-mi's case. But officials have withheld details about exposure levels and how the company's chemicals are managed. "Our fight is often against trade secrets. Any contents that may not work in Samsung's favour were deleted as trade secrets,'' said Lim Ja-woon, a lawyer who has represented 15 sick Samsung workers. Lim's clients have been unable to see full, third-party reports on inspections of the factories and have accessed only excerpts of some independent inspections in some court rulings, he said. Samsung says it has never "intentionally'' blocked workers from accessing information and that it is transparent about all chemicals it is required to disclose to the government. It said in a statement that there was no case where information disclosure was "illegally prevented.'' "We have a right to protect our information from going to a third party,'' Baik Soo-ha, a Samsung Electronics vice-president, told the AP.

JK Shin, president and CEO of Samsung Electronics, holds the Samsung Galaxy S6 Edge Plus, left, and the Samsung Galaxy Note 5 during a presentation, Thursday, Aug. 13, 2015, at Lincoln Center in New York. (AP Photo/Mary Altaffer) Government policies have generally favoured Samsung and other "chaebols,'' or corporate conglomerates, that powered South Korea's rapid industrialization after the 1950-53 Korean War. Officials say corporate interests take priority, evaluating trade secrets claims is difficult, and they fear being sued for sharing data against a company's will. "We have to keep secrets that belong to our clients,'' said Yang Won-baek, of the Korea Occupational Safety and Health Agency, or KOSHA. "(Samsung) once offered me 1 billion won ($864,000), asking me to stay silent. The idea was to deny her illness was an occupational disease and to leave me without any power to fight back.'' — HWANG SANG-GI, father of Hwang Yu-mi, a former Samsung factory worker who died of leukemia at the age of 22. Hwang launched a movement seeking independent inspections of Samsung factories. ​ Samsung is by far South Korea's biggest company, with about 100,000 workers. It has dominated memory-chip makers since the early 1990s, but that success involves use of toxic and often carcinogenic chemicals such as arsenic, acetone, methane, sulfuric acid and heavy metals such as lead, well-known risks in the production of semiconductors, mobile phones and LCDs. The worker safety group Banolim, or SHARPS in English, has documented more than 200 cases of serious illnesses including leukemia, lupus, lymphoma and multiple sclerosis, among former Samsung semiconductor and LCD workers. Seventy-six have died, most in their 20s and 30s. Worker safety advocates want South Korea's courts and government to more flexibly interpret links between workplace conditions and diseases, since the exact causes of many of the factory workers' ailments are unknown even to the medical community. They also want thorough disclosure of workplace hazards.