Tianjin Port Holdings, the listed entity of the port's main operator, said it understood from the Xinhua website that its chairman, Zheng Qingyue, was being investigated for dereliction of duty and its vice-chairman was temporarily taking over his duties.
The company was operating normally, it said in a stock exchange statement.
Separately, the state prosecutor said on its website an investigation of the blasts had found officials from a range of agencies to have been irresponsible, negligent and lax in the supervision of Tianjin Ruihai.
Among these agencies were Tianjin's transport, land resources, work safety and customs offices, besides state-owned port companies.
It named 10 officials suspected of dereliction of duty and one suspected of abuse of power.
The death toll from the blasts that flattened part of the port, the world's 10th busiest, has risen to 145 with 28 people still missing, the Tianjin government said on its Weibo social media account.
Tianjin Port Holdings, the listed entity of the port's main operator, said it understood from the Xinhua website that its chairman, Zheng Qingyue, was being investigated for dereliction of duty and its vice-chairman was temporarily taking over his duties.
