Hanoi, Sep 21 (DPA) Three workers at a fish sauce factory suffocated when they entered a fermenting vat and inhaled a toxic gas, Vietnamese press reported Monday.

The newspaper Nong Nghiep (Agriculture) reported that Bui Dinh Tuan, 36, had climbed into a fish sauce vat to repair a pipe Saturday morning at the factory where he worked in the coastal town of Cam Ranh.

When Tuan passed out, two co-workers, identified as Nguyen Huu Tai and Tran Thin, attempted to rescue him, but were overcome by fumes as well.

The newspaper said four workers at a different fish sauce factory in Cam Ranh had died of methane inhalation in a similar accident in 2000.

Fish sauce, or 'nuoc mam,' made of crushed and fermented fish, is a widely used condiment in Vietnamese cuisine.