BEIHAI, Guangxi: Fifty-five food factory workers were being treated for carbon monoxide poisoning, including five who are seriously ill, in south China's Guangxi Zhuang Autonomous Region, Monday, doctors said.

The workers from Beilian Food Co., Ltd., Hepu County, Beihai City, had started arriving at Beihai Municipal People's Hospital from 5 am, according to the hospital records.

All the workers, one man and 54 women, fell ill while working in the room where carbon monoxide was used to keep aquatic products fresh, said a manager surnamed Huang of the company.

"I felt dizzy and nauseous while working the night shift and was sent to the hospital early this morning," said a woman who was receiving an intravenous drip.

The company has suspended production. Beihai Municipal Bureau of Work Safety is investigating the cause of the incident.