Inside Apple's Pegatron Supply Chain In Shanghai

Bloomberg was offered an exclusive look at one of Apple Inc. AAPL's factories that has come under fire for forcing its employees to work long and grueling hours.

The factory, owned and operated by Pegatron, collaborated with Apple to adopt new procedures to fix its labor related issues.

Pegatron is the world's biggest contract electronics manufacturer after Foxconn, according to Bloomberg Intelligence.

The factory is "one of the most secretive facilities at the heart of iPhone production and covers an area equal to almost 90 football fields," the Bloomberg report noted. To move employees around, the factory is equipped with shuttle buses, cafeterias and even has a firehouse, police station and post office.

However, the factory "still hides a secret," Bloomberg added. According to China Labor Watch, base pay remains "so low that workers need overtime simply to make ends meet." The organization noted that it has collected 441 pay stubs that "point to continued excessive overtime."

On the other hand, Pegatron insists it has done no wrong and sticks to government guidelines of capping overtime at roughly 80 hours a month.

"Manufacturing is not a sin," Denese Yao, a Pegatron employee who oversees the company's relationship with Apple told Bloomberg. "People think we're just squeezing everything out of the workers. We need to let them know what is an efficient and responsible working environment."