Soccer wear and shoes from three international sports brands, all of whom are major producers of apparel for the upcoming World Cup in Brazil, were found to contain toxic chemicals, according to a report issued by Greenpeace on Monday.

In its report, the environmental organization said it bought sporting goods from Nike, Adidas and Puma in 16 countries and regions across the world and conducted tests on them from March to May. It found that 81 percent of the three brands' soccer shoes and 35 percent of their soccer performance shirts had chemical residues, including plasticizer and perfluorinated compounds.

Among the tested products, the perfluorooctanoic acid index of an Adidas soccer boot named Predator had more than 15 times the standard amount of the acid, the report said.

The perfluorooctanoic acid, or PFOA, is often used to make textiles waterproof and difficult to degrade, said the report, which added that the chemical could impact fertility after a long period of human contact.

The chemical has been listed as a high-profile substance under European Union rules. Animal tests have also shown that PFOA may cause cancer, according to the report.

Li Yifang, director of Greenpeace's project to prevent pollution, said the chemical is currently banned in some countries and regions, including Norway. A few companies, such as Adidas, have said that they had already eliminated the toxic substance from production.

"It is a huge disappointment that Adidas has moved backward compared with other companies," Li said.

Greenpeace has advised consumers and soccer fans not to buy the products made with toxic chemicals.

"These polluted sports shirts and soccer shoes worn by athletes in competition will be against the environmental ideals of the World Cup in Brazil," Li added.

The NGO urged the three sports brands to disclose toxicity information about their products as soon as possible and suggested that they establish a clear timeline to eliminate toxic chemicals from production lines and take specific measures to provide environmentally safe goods for consumers.

Chen Wenze at Burson-Marsteller, public relations partner of Adidas, said the company would not make any comments on the Greenpeace report. The marketing and operations departments from Adidas did not answer phone calls from China Daily on Monday.

Hu Jianying, a professor specializing in pollution at Peking University, said PFOA is not only used for sports performance shirts, but also other clothing and could cause skin irritation.

Hu said consumers should wash the shirts before wearing them.

"Factories and companies should control the amount of PFOA they use in producing goods," she added.

According to the China National Textile and Apparel Council, there is no current standard on the use of PFOA to make sporting goods in China.

PFOA is often seen in agricultural products and polluted water, an official of the council, who declined to be identified, said. He confirmed most cleaning products, such as laundry detergent, contain the chemical and that it will easily remain on clothes if consumers do not wash them well.

"The key to alleviating the problem is to wash clothes, no matter if they're new or old, in clean water several times," he said.

Sun Xiaochen contributed to this story.