By staff reporter Zhao Jianfei

A boardroom upheaval at Sinopec, Asia’s largest oil refiner, has been linked to a government detention of the company’s former chairman.

The company said Chen Tonghai stepped down from the top job as Sinopec chairman and general manager for personal reasons, but Caijing learned that he was being questioned by Communist Party investigators. It’s unclear why.

Chen was succeeded by Su Shulin, 45, a former vice president of PetroChina.

At PetroChina, Su tackled several crises, including a 2004 gas well explosion in Chongqing that claimed 243 lives. Su’s appointment with Sinopec will make him the youngest head of a ministry-level enterprise.

Su’s appointment was announced after a high-profile meeting of central government officials June 22. A meeting participant told Caijing that Chen was present, but later stepped out of the meeting hall and was not seen again.

That evening, Sinpoec held a nationwide videoconference with its affiliates. The newly appointed Su delivered a speech.

“Since I am about to take this job, I am feeling heavy pressure on me,” he said. “I deeply understand that the tenure is limited but my responsibility is infinite.”

At the same time, Sinopec (SH 600028 and HK0386) announced than Chen had resigned from his posts as the board chairman and member of the board for “personal reasons.”

Investors reacted by selling the company’s stock, citing the suddenness of the leadership change and related rumors.

The first trading day after the switch, Sinpoec share prices fell 5.7 percent on the Shanghai exchange to 13.47 yuan. In Hong Kong, its H share prices fell 2.8 percent to 8.79 HK dollars.

The rating agency Standard & Poor’s (S&P) said Chen’s departure would not have a substantial impact on Sinopec’s rating. S&P said it would meet company managers in the third quarter to assess the company’s operation and financial conditions, including management.

Su’s difficult background as the son of a poor family in Heilongjiang Province helped him develop a working style of “persistence and caution,” said his former colleagues at ChinaPetro.

Born into a poor family, Su and six siblings were raised by their widowed mother. According to a profile on the Web site of the China National Petroleum Corp. (CNPC), Su majored in geological exploration and engineering management. He spent 14 years working on exploration at the Daqing Oil Field, once China’s largest.

In 1997, Su was promoted as deputy director of Daqing Oil Administration Bureau and was assisted by Ma Fucai, former deputy general manager of PetroChina and director of the Daqing Oil Field Administration Bureau. An industry insider told Caijing that Ma appreciated Su’s ability and trained him to be his successor.

Two years later, Su was promoted to vice-general manager of CNPC, board director of Daqing Oil Field Co. Ltd. Su was appointed senior vice-president of PetroChina in 2002, and later that year elected as an alternate to the 16th Central Committee of the Communist party. He was then 40, becoming the committee’s youngest alternate.

Ma was forced to resign after the natural gas explosion. But rather than succeed Ma, Su was transferred to Liaoning Province in the northeast, where he currently serves in government and party positions.