The environmental campaign group Greenpeace has accused major Chinese textile companies of discharging harmful chemicals into the country’s major water systems, reported The Guardian.

In its one-year investigation, Greenpeace campaigners collected samples from the discharge pipes of various textile plants and sent them for analysis to laboratories in Europe. One of these facilities in Ningbo, Zhejiang province, operated by the major textile group Youngor, was found to have discharged a range of toxins including nonylphenol and perfluorinated chemicals. These chemicals are not illegal in China, but they are banned in many developed countries.

Another polluter accused in the report was Well Dyeing Factory in Zhongshan, Guangdong province, which was reported to have discharged a range of heavy metals and organic chemicals. Greenpeace claimed the factory released hazardous effluent into the Shiji River at night so as to avoid detection by governmental inspectors.

Youngor, which has business relationships with a number of well-known Western fashion brands, has reportedly agreed to work with Greenpeace to eliminate toxic chemicals. Well Dyeing has denied it has a problem.