BEIJING -- Beijing consumer watchdogs are investigating how Wal-Mart, Carrefour and other leading chain stores came to be selling clothes containing cancer-causing chemicals.

Twenty-eight brands of clothes failed inspections by the Beijing Industry and Commerce Administration (BICA), and four brands were found to contain excessive levels of toxic aromatic ammine or formaldehyde.

The four brands were "Ming-Langdike" skirts (size 11) made by the Guangzhou Disheng company, "Pusheng" blouses (155/80A) by the Shanghai Pusheng, "Jeanberger" trousers (170/80A) by the Shenzhen Zhonghang and "Hafulu" trousers (size 23) by the Guangdong Hafulu.

The full list of failed items has been published on the BICA website.

Experts said aromatic ammine and formaldehyde were both carcinogenic substances. The former is banned in many other countries as a dye and the latter should be cleaned from end products.

The BICA said it seized all failed clothes from the stores, and both the producers and sellers would face prosecution.

"They could be fined up to three times the revenue they got from selling the goods," an official with the administration said.

"The problematic trousers are no longer sold in our stores," a Wal-Mart representative said, adding he was unaware of the investigation.

Carrefour's Fangyuan chain store, Lotus Liuliqiao chain store and Wangfujing Women's Collection were also listed for selling clothes that failed inspections.