A total of 184 people were hospitalised in central China's Hubei province after suffering sulphur dioxide poisoning, the state media reported on Tuesday.
All but ten were discharged later.
The accident occurred on Sunday evening when sulphur dioxide leaked from the Hubei Yihua Dajiang Fertiliser Co, Xinhua news agency reported.
The leakage sent 184 local residents living more than a kilometre from the site to hospital, local officials said.
By on Monday noon, 163 had been released from hospital while 10 were still being treated for poisoning.
The cause of the accident is under investigation.
Chinese cities are increasingly witnessing industrial accidents amid rapid industrialisation.
The last major industrial accident was reported on August 27 when a chemical spill killed one person, seriously burnt another, and polluted a source of drinking water for one lakh residents in northwest China's Shaanxi province.