More than 20 workers were hurt when the rest shelter at a Cambodian factory collapsed, just days after portions of another garment plant in the country caved in, killing three people and injuring several others.

The concrete and metal structure, where workers were resting during their lunch break, collapsed into a pond behind the factory operated by Hong Kong-based Top World Garment (Cambodia) Ltd. in Phnom Penh, reports the Wall Street Journal.

Local police said 23 workers were injured, including a pregnant woman. No fatalities were reported. Authorities were still determining the cause of the structure’s collapse.

“It was an incident we couldn’t expect,” said Koch Ousphea, chief administrator at the factory which produces garments for Swedish retailer H&M.

The latest incident adds to concerns about safety in the garment industry in Cambodia after the ceiling of a shoe factory crumpled to the ground, leaving three workers dead and at least six injured.

A more-deadly factory disaster has killed more than 1,000 people in Bangladesh last month after an eight-storey garment building collapsed, highlighting the unsafe working conditions in the region.