China's cabinet also ordered officials to "crack down unwaveringly on illegal activities to ensure safety".
The operators of the Tianjin site have been accused of "clearly violating" safety rules.
Fires were still burning 36 hours after the blasts, and chemical experts are testing for toxic gases.
There was one bright moment on Friday when 19-year-old firefighter Zhou Ti was pulled from the rubble alive. But 21 firefighters are reported to be among the dead and several more are missing.
The cause of the blast is still being investigated.
In a report, Xinhua said the cabinet, the State Council, had ordered "governments at all levels to reinforce the safety management on dangerous chemicals and explosives".
They should "firmly implement special regulatory measures for highly toxic chemicals such as cyanide, as well as inflammable and explosive materials".
The reference to cyanide followed reports in the People's Daily that 700 tonnes of sodium cyanide were at the Tianjin site. Ammonium nitrate may also have been present.
Officials have only confirmed that calcium carbide, potassium nitrate and sodium nitrate were at the warehouse.
Chinese officials, though, have admitted there are discrepancies between accounts from the company and from customs, and that damage to company offices had made it hard to identify the chemicals.
More than 200 chemical and biological experts from the military are on site but officials insist that the air and water quality levels in Tianjin are safe.
However, the People's Daily quoted the Beijing News as saying that sodium cyanide had now been detected in the sewage and leakage had been confirmed.
Many residents could be seen wearing air-filtering masks. One, Ma Wiehan, told Associated Press: "I don't usually wear a mask but I don't quite trust what the government says."
People's Daily said the Tianjin facility, operated by Ruihai Logistics, had "clearly violated" safety rules that say dangerous materials must be stored at least 1km (0.6 miles) away from public buildings and main roads.
