At least 15 people were killed when ammonia leaked from a frozen storage and logistics business in Shanghai on Saturday, according to local news reports.
According to The New York Times, the leak at the business, in the Baoshan district, also left eight people seriously injured and 17 with lesser injuries, said a Chinese television news report, citing industrial safety officials.
The reports did not specify how the people died or say whether they were all employees at the site. Safety officials said they were investigating the cause of the leak, which sent stinging fumes into nearby residential areas.
The Chinese government has said it is trying to reduce deaths at mines, factories and other workplaces that became more dangerous in the wake of rapid industrial growth.
In June, explosions and a fire set off by a gas leak tore through a poultry plant in northeast China, killing at least 119 people.
Poorly placed exits and blocked doors prevented many people from escaping, survivors said. That was the worst industrial accident in China in recent decades.
The government has not issued detailed data for recent industrial accidents. It has said that in 2011 the number of people killed in mines, factories and other workplaces fell to fewer than 10,000.