Shanghai, Feb 18 (IANS): Students in 21 primary and middle schools here were ordered to stop wearing their uniforms Monday after a toxic dye was found in the products of a garment firm.

In a recent quality inspection campaign, aromatic amine dye, which can cause cancer, was detected in one batch of student uniforms produced in July 2012 by the Shanghai Ouxia garment company, reported Xinhua citing the Shanghai Municipal Bureau of Quality and Technical Supervision.

Six batches of the company's clothes products were substandard, said the city's quality watchdog. The company has been one of a number of producers of school uniforms in Shanghai for five years.

Education authorities in the Pudong New Area of Shanghai, in a statement, said they have demanded that the 21 schools who had purchased uniforms from Ouxia tell students to stop wearing the clothes, which require quality examination.

The company, which has stopped production, sold 15,000 school uniforms annually.