PetroChina Chuandongbei natural gas field explosion, Guoqiao, Kai County, Chongqing, China, killing at least 234.

Kaizhou District (Chinese: ), formerly known as Kai County, Kaixian or Kaihsien (Chinese: ) is a district under the jurisdiction of Chongqing Municipality, in southwestern China, bordering Sichuan province to the west. It has an area of 3,959 square km. As of the end of 2009, it had a population of 1.62 million. It is located 330 kilometers from the urban centre of Chongqing proper.

PetroChina Company Limited (simplified Chinese: 中国石油天然气股份有限公司; traditional Chinese: 中國石油天然氣股份有限公司) is a Chinese oil and gas company and is the listed arm of state-owned China National Petroleum Corporation (CNPC), headquartered in Dongcheng District, Beijing. The company is currently Asia's largest oil and gas producer and was China's second biggest oil producer in 2006. Traded in Hong Kong and New York, the mainland enterprise announced its plans to issue stock in Shanghai in November 2007, and subsequently entered the constituent of SSE 50 Index. In the 2020 Forbes Global 2000, PetroChina was ranked as the 32nd-largest public company in the world.