A monthlong investigation by FLA revealed compensation issues, health and safety risks, and issues that have led to a "sense of unsafe working conditions among workers," the organization said in a statement.

FLA claimed it gave Foxconn "a full-body scan through 3,000 staff hours," and surveyed more than 35,000 workers, while investigating three of its factories. Foxconn Technology Group, owned by Hon Hai Precision Industry, is Apple's largest supplier and makes the iPad and iPhone. Independent groups have urged Apple to address the poor conditions of factory workers in China.

Foxconn has been under scrutiny over the past few years, following a string of suicide attempts at facilities in China. The company came under fire again earlier this year after published a story describing poor working conditions at Chinese factories operated by Apple contractors. Nonprofit organizations such as Change.org are running campaigns calling for Apple to address the issue and make products ethically.

Apple CEO Tim Cook has , saying the company is leading the way in improving working conditions. Apple also acknowledged violations related to issues such as wages, underage labor and working conditions issued in January.