In September, U.S. clothing brand Gap made its supplier list available -- consisting of nearly 900 garment factories in Bangladesh, Cambodia and other countries. The company said it had revised its disclosure policy for supply-chain information seeking to promote global sustainability.

According to Human Rights Watch, an international nonprofit nongovernmental group, at least four major retailers, including Gap, C&A of Germany and British store chain Marks & Spencer, have disclosed their supplier list this year. Previously, Gap was known for its negative stance on the disclosure due to what it called "competition reasons."

Earlier adopters of the disclosure include U.S. sport brand Nike and H&M, the Swedish fast fashion chain. Nike's supplier list includes details about its contract factories such as the number of workers by location and the proportion of female and immigrant labor.

Seeking endorsement from society

Major Western apparel brands and retailers are particularly keen on disclosing their factory list, said Takeshi Shimotaya, a London-based consultant. The lists have been considered closely guarded trade secrets for many manufacturers because making them public could lead to information leaks about specific products. Providing the names of skilled subcontractors to competitors could also harm competitiveness.

Nonetheless, the idea is rapidly spreading around the world that leading manufacturers should be responsible for the working conditions of their subcontractors.

In the late 1990s, Nike was criticized by the international community for ignoring the child labor at its factories in developing countries.

In 2013, a building collapse in the Bangladesh capital of Dhaka killed more than 1,000 workers of factories that manufactured garments for many popular Western brands, including H&M. The accident raised criticism that these brands did not care about the human rights of their subcontractors and led many of them to review their supply chain policies.

Among non-apparel manufacturers, Apple was one of the earliest to make its supplier list public. In the early 2000s, the company was condemned for squalid working conditions at its factories in China. In 2006, the company began improving the working environment of its subcontractors' factories and disclosed the supplier list.