Chinese authorities have ordered evacuations for all residents living within a 3km radius from the part of the city of Tianjin where port warehouse containers exploded on Wednesday.
Police have confirmed that the highly dangerous chemical sodium cyanide was found in the area. Fires have reignited sporadically on the site of the twin explosions.
The list of chemical substances possibly onsite also include sodium bisulfide, potassium nitrate and ammonium nitrate, according to Tianjin work safety official Gao Huaiyou.
The evacuations are a security precaution in case any toxic gasses have contaminated the air, according to Chinese state news agency Xinhua. People leaving the area have been asked to wear long trousers and cover their faces with masks.
Beijing News had previously reported an unidentified yellow foam on the site.
The death toll from the explosions has risen to 85, authorities confirm on Saturday. More than 700 people are still in hospital undergoing treatment.
The Chinese port city of Tianjin is home to 15 million people. Frustration has been building over the lack of information available to residents, especially among relatives of the deceased.
“Nobody has told us anything, we’re in the dark, there is no news at all,” Al Jazeera reported one woman interrupted a press conference.
Authorities are still investigating the cause for the explosions.
The fires caused large damage to the goods awaiting shipment in the port. The port handles a variety of goods, including cars, steel, and crude oil.