Chinese police have for the first time confirmed deadly sodium cyanide at the site of two huge warehouse blasts that killed 85 people, state media said on Saturday, as a series of new, small explosions were heard and small fires broke out.

Police confirmed the presence of the chemical, fatal when ingested or inhaled, “roughly east of the blast site” in an industrial zone in the northeastern port city of Tianjin, the state-run Beijing News said.

It did not say how much had been found or how great a risk it posed, Reuters reported today.

The blasts late on Wednesday originated in a warehouse storing toxic chemicals and some residents expressed concern that the air and water could have been poisoned.

“I do feel a bit afraid,” said construction worker Li Shulan, 49, when asked about the air quality. “It definitely doesn’t feel good. As you can see our boss is making us wear masks.”

An area three km (two miles) from the site was cordoned off while one school, which had been set up as a safe haven for residents living close to the danger area, had since been evacuated, the Beijing News said. It did not give a reason.

There were about seven small explosions in the area on Saturday, according to a post on the micro-blog of the official China Central Television. A Reuters witness said a fresh blaze ignited cars in a parking lot next to the blast site. The cause was not immediately clear. State media carried reports of other fires in the area.