Apple has come under unprecedented pressure to halt the use of harmful chemicals in its factories. The chemicals in question include the solvents n-hexane and benzene, which have been shown to cause nerve damage, paralysis and the development of cancers.
The comments were made by pressure groups China Labor Watch and Green America, but stopped short of calling for a customer boycott of Apple products.
The groups urged Apple to "stop needlessly exposing workers in Chinese manufacturing facilities to toxic chemicals now causing severe illnesses."
They added that using toxic chemicals rather than alternatives saves Apple a "shockingly small amount of money".
The solvent n-hexane, which can be found in gasoline, is used to clean electronic displays, including Apple's iPhone. It is preferred over traditional solvents such as isopropanol simply because it evaporates faster, and therefore speeds up the manufacturing process. However, it has been shown to cause nerve damage and paralysis.
Benzene is used as a cleaning and coating agent for electronic components. However, it can cause vomiting and dizziness in even low doses, and has been linked with the development of leukemia
Kevin Slaten, programme co-ordinator at China Labor Watch told the press: "Together with Green America, we demand that Apple takes responsibility and removes chemicals like the solvents n-hexane and the carcinogen benzene, which is known to cause leukaemia," as well as "providing its workers with a legal standard of welfare."
An Apple spokesperson told the Guardian that it requires all its suppliers to meet or exceed the safety standards for the handling of hazardous chemicals set by the US Occupational Safety and Health Administration (Osha), which is 500 parts per million (ppm) for n-hexane in general industry or 1.8g per cubic metre, and 1ppm for benzene.
However, Slaten has accused Apple of inadequate training of its staff in the handling of toxic chemicals.
"When workers come to these factories they deal with harmful chemicals every day and they need to be educated about them. Unfortunately training in most factories is not adequate with some receiving as little as 10 minutes pre-job rather than the 24 hours legal requirement," Slaten explained.
Apple's major competitors were also blamed for similar breaches.
"[Apple] is not alone in these labour conditions breaches," Slaten said. "Samsung, HP, Dell and others all need to reform too."
Apple has been criticised in the past for its working conditions. In 2012, it agreed to pay for higher working conditions in its Foxconn factories after waves of protest forced its hand.