The potentially cancerous toxic chemical, Lentine, has been found in five brands of hair dye in China.
According to a China Daily report, local consumer authorities said in Guangzhou on Monday that while the link between hair dye and cancer is still unproved, the five well-known international brands found with the toxic substance included Revlon Color Silk, Ecosystem No 1 Hair Colorant, Sewame Eshine Colorants, Kangchen 3in1 and Ouwaiya hair dye (natural black).
All of them are produced in the southern Chinese province of Guangdong.
The hazardous elements were detected after the Guangdong provincial consumer commission checked hair dye produced by 21 companies early this year.
"The presence of lentine, widely used as a highly toxic industrial dye, is banned in hair dye," Guo Yuhua, spokesman of the Guangdong provincial food and drug administrative authority, was quoted, as saying.
Inhaling lentine vapor could cause respiratory diseases. If the skin absorbs the chemical, it may damage kidney and liver, Guo said.
The authority warned consumers to conduct an allergic test before using "any brands of hair dye".