Industrial accidents are common in China, where work safety regulations are often flouted.
In the first eight months of the year, China saw 232 chemical accidents which killed 199 people and injured 400, Greenpeace said in a statement.
"China's chemicals industry is the largest in the world, but it is appallingly under-regulated," said Cheng Qian, its East Asia toxics assistant manager.
"Tragic accidents occur on an almost daily basis."
The report comes a little over a year after massive explosions in the northern port city of Tianjin killed at least 165 people, sending a monumental fireball skyward and mangling structures kilometres away.
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Leaks were the cause of 43 percent of the accidents, followed by fire and explosions.
Most of China's 33,000 chemical facilities are concentrated in the densely-populated east, Greenpeace said.
China must thoroughly reform its chemicals management policy to ensure health and environmental safety, it added.
Earlier this summer more than 130 people were taken to hospital after chemicals leaked from a plant in eastern China.
In April a chemical fire burned for 16 hours in the coastal province of Jiangsu after an explosion at a facility storing chemicals and fuel. Some 400 firefighters were needed to quell the flames.
A government inquiry recommended that 123 people be punished.