The lack of oversight is apparent in the questions being asked about what was being stored in Tianjin warehouse. Chinese authorities say they aren't sure, as the facility's managers provided "insufficient information."
Military inspections at the blast site Sunday revealed "several hundred tons of cyanide material" at two locations, said Major General Shi Luze. Authorities are checking customs records for more clues as to exactly what was being held.
The "cyanide material" was sodium cyanide, a highly toxic substance used to extract precious metals in the mining industry, among other uses.
"Sodium cyanide is a very toxic chemical. It would take about a quarter of teaspoon to kill you. Another problem with sodium cyanide is that it can change into prussic acid, which is even more deadly. So the whole business is trying to clean up this mess is difficult," chemical risk consultant David Leggett told CNN.
Environmental group Greenpeace said it believed other dangerous chemicals stored at the site included toluene diisocyanate and calcium carbide, citing a local monitoring station.
Leggett said he found it "hard to believe" there were only a handful of different types of chemicals in the Tianjin warehouse: "I would have expected a lot more than that," he said.