BEIJING (AP) — At least 15 people were killed Saturday after liquid ammonia leaked from a refrigeration unit at a cold storage plant in China's financial hub of Shanghai, the local government said.

Twenty-five people were injured in the accident, which happened at a plant in the Baoshan district of the east coast city, the Shanghai government Information Office said. Five of the injured were in serious condition.

The government identified the plant as Weng's Cold Storage Industrial Co. Ltd., but gave no further details. The cause of the leak was not immediately known and investigations led by the city's work safety bureau were under way, it said.

The Information Office said an environmental monitoring station in the district did not detect any negative impact from the leak.

Industrial accidents are common in China due to lax safety and building standards.