China has accused 11 government and port officials of negligence over the massive explosions that killed 139 people in Tianjin earlier this month.
It remains unclear whether they have been taken into custody.
However 12 company executives have now been formally detained, mostly from Ruihai International Logistics, which owned the warehouse that blew up.
The 12 August chemical explosions sent a huge fireball in to the sky and destroyed hundreds of homes.
At least 34 people are still missing since the blast, more than 500 are still in hospital and thousands have been unable to return home.
The explosions sparked concerns about the storage of dangerous chemicals and planning regulations.