The Consumer Council has warned about carcinogenic dyes in some textile materials being used for school uniforms in Hong Kong.
The watchdog said in a press release Monday that it tested 49 school uniform samples and found that two of them contained carcinogenic azo dyes.
The two samples were a Lingnan Secondary School blouse made by school clothier Sing Shun Fat and a school dress of Fung Kai No.1 Secondary School purportedly from a maker named Sum Yi, according to reports.
The Council found 173 milligrams per kilogram (mg/kg) in three grey cloth embroidered trimmings on the blouse, as well as 41 mg/kg in the checkered pattern waist belt of the dress of Fung Kai No.1 Secondary School.
Wong Yuk-shan, chairman of the consumer protection body, noted that azo dyes will form carcinogenic 4-amino azobenzene with sweat, which can be absorbed through the skin.
Europe, Japan, and China have prohibited the use of azo dye in textiles because of the risks of release of harmful chemicals.
The Council emphasized in its press release that the finding was “most unsettling”, although the substances were only found on trimmings on the uniforms rather than the main fabric.
The deputy principal of Lingnan Secondary School, Lo Kam-yiu, said the uniform provider of the school was changed two years ago, the Hong Kong Economic Journal reports.
The school had advised students, through an online notice on Sunday, to stop wearing the uniforms in question.
The owner of Sing Shun Fat, a person surnamed Yiu, confirmed that they had not produced Lingnan’s uniforms for two years.
Yiu said they had handed over all 17 Lingnan uniforms in storage to the customs.
He was confused, he added, as he noted that even though he trimming was made of the same fabric as the skirt, the council did not find the skirt problematic.
The principal of Fung Kai No.1 Secondary School, Wong Tsang-cheung, said Sum Yi had never been their uniform supplier and claimed the uniform examined in the report was a counterfeit.
Given the use of their school badge in the uniform, the school reserved the right for legal action, Tsang said.
Sum Yi said the uniform containing azo dyes was made 10 years ago and that it had stopped selling them after the contract was terminated.
Besides azo dye, the Council found eight samples that contained formaldehyde and two with pH values exceeding even the Chinese standard.
Also, the watchdog found endurance performance of the samples unsatisfactory.