BEIJING, Nov. 10 -- An unlicensed washing-up liquid factory, which sold potentially cancer-causing detergent to more than 300 restaurants in Beijing, was closed down on Tuesday.

    Hidden in a 12-square-metre room in Beijing's Chaoyang District, the factory had sold 54 tons of toxic detergent since May, the district's administration for industry and commerce said.

    Detergents were being produced using an industrial chemical called SLESN70, a strongly acidic liquid normally used to clean machinery and pipelines.

    According to doctors, long-term exposure to the chemical could cause ulceration of the digestive system and even cancer of the oesophagus.

    According to records seized from the illicit chemical plant, more than 300 Beijing restaurants bought detergent from the factory.

    While most customers were small independent restaurants, some five-star hotels also appeared on the list, including the Beijing International Hotel.

    A public relations officer for the hotel, Ma Hong, told China Daily that the detergents were purchased and used by two restaurants that rented rooms at her hotel.

    "The hotel itself did not use these detergents at all," Ma said, adding that the hotel has urged the two restaurants to investigate the case.

    The Chaoyang Administration of Industry and Commerce said it was working with health and quality supervisory agencies to trace use of the harmful detergents.

    An administration official named Wang Xiaodong said his agency had been tipped off about the factory.

    "It is the first time the administration has shut down an illegal detergent factory and from now on we will check detergent-makers more frequently," he said.

    The owner of the illegal factory is a middle-aged man from East China's Anhui Province.

    All the detergents were made by the man and his wife. The couple now face severe legal punishment.

    Cheng Xiaojun, a member of the China Detergent Industry Association, said the base materials for detergents must be chemically neutral so their residues do not harm people's health.

    "SLESN70 should absolutely not be used in civilian detergents," Cheng said.

(Source: China Daily)