The Beijing News on Saturday said all people within a 3-kilometer radius of the Tianjin warehouse explosion site are being forcibly evacuated from the area because of a possible chemical contamination.
Sodium cyanide was detected east of the site, according to police cited by the paper.
China confirmed Sunday that sodium cyanide, a toxic chemical, was stored in the warehouses devastated by massive explosions last week in the port city of Tianjin.
Shi Luze, chief of staff of the People's Liberation Army's Beijing Military Region, said more than 100 tons of the deadly chemical was stored in two locations within the blast site.
Sodium cyanide can form a flammable gas upon contact with water, and several hundred tons would be a clear violation of rules cited by state media that the warehouse could store no more than 10 tons at a time.
Chinese officials also said Sunday the death toll from the blasts has risen to 112. At least 21 firefighters are among the dead, state media reported.
More than 700 people were injured and nearly 100 people are missing, including 85 firefighters.
Smoke rises among shipping containers next to damaged vehicles as firefighters try to put out a fire after explosions on Wednesday night, at Binhai new district in Tianjin, China, Aug. 14, 2015.