TIANJIN, Aug. 15 -- Specialists investigating Wednesday's explosion in Tianjin believe sodium cyanide might have been stored at the site.

At a press conference Saturday morning, Gao Huaiyou, vice head of the Tianjin bureau of work safety, said that chemicals stored in the warehouse possibly include sodium cyanide, but further confirmation is needed. The containers were not open, and some were not even registered.

Some local media reported earlier that Rui Hai Logistics, owner of the warehouse, had as much as 700 tonnes of sodium cyanide, but Gao said it was not yet verified.

Measures have been taken to prevent secondary disasters, such as inviting sodium cyanide producers to help at the site, using hydrogen peroxide to reduce the amount of sodium cyanide, sending a taskforce to locate and measure the contaminated area and prevent its spread in sewage.

Some other dangerous chemicals likely to be stored include potassium nitrate and ammonium nitrate.