A factory in Shenzhen, China, that assembles iPhones and other Apple products, has reportedly witnessed 13 workers aged between 19 and 24 diagnosed with cancer. Five have died from the disease.
An investigation by the Mail on Sunday found that the factory workers had contracted leukaemia, potentially as a result of exposure to dangerous cleaning chemicals used in the plant.
Apple has previously been accused of dangerous working conditions in its Chinese supply factories, with advocates from Labour Action China, Green America and China Labour Watch (CLW) all previously campaigning for improved welfare.
Earlier this month, an investigation by CLW and Green America found that one of Apple's assembly plants in Suqian, China, was responsible for endangering the safety of up to 20,000 workers.
Following similar accusations regarding the welfare of factory workers in 2013, Apple claimed that it no longer used hazardous chemicals, such as benzene and n-hexane.
The California-based company said that it required production facilities to meet the safety standards for the handling of hazardous chemicals as set by the US Occupational Safety and Health Administration.
"The new report demonstrates that in the 16 months, Apple has not made progress with this supplier to improve conditions for its workers," CLW said in a statement, referring to the findings of its most recent investigation.
"In spite of Apple's supplier code of conduct and commitments to prevent these violations, more than a year later, they persist."
According to the Mail on Sunday report, workers that fall sick with leukaemia in the factories are dismissed and denied continuing medical coverage, resulting in the bankrupting of families unable to afford medical treatment.
Foxconn, the supplier that runs the Shenzhen factory, has said that it is set to meet with members of Labour Action China to find out more about the leukaemia cases. It claims that there is no evidence to link the deaths to dangerous chemicals.