Nuclear and biochemical experts have been sent to Tianjin after at least 50 people were killed in two huge explosions in the northern Chinese city.
State media reported that a team from the International Atomic Energy Agency's Beijing environmental emergency response centre had been dispatched to the scene.
In addition, 214 Chinese military nuclear and biochemical materials specialists have gone to the port city as investigations continue into the blasts in an industrial area.
Police in Tianjin, China, have reportedly said they are unsure what toxins and chemicals may have been released in yesterday's warehouse explosions.
According to NBC Correspondent Ian Williams the fact that officials are unsure what was in the warehouses when the explosions happened is making the task of firefighters harder as it is unclear what is still fuelling the fire.
Survivors of the explosions in China which killed at least 50, and injured more than 700, have spoken of the moment they were caught up in the blasts.
One survivor, a security guard at the Tianjin warehouse site where the blasts originated, told ITV News how his quick thinking had saved his life.
He said: "Suddenly I heard the explosion and I lay down straight away but I still got injured. The security booth was completely destroyed."
ITV News Correspondent Rebecca Barry reports:
Satellite imagery has been released today showing the view from above, just moments before and after, the site of a series of explosions in the Chinese city of Tianjin.
In the first image the warehouse district where the blasts happened looks calm but moments later thick black smoke can be seen rising from the tops of what looks like buildings below.
Drone footage from above the site of yesterday's China explosions has shown the scale of damage caused by two blasts in the city of Tianjin's warehouse district.
In the footage, posted on the El Regional newspaper's YouTube channel, fires can be seen burning in the midst of burnt out buildings and explosion wreckage as black smoke billows into the sky.
Fires are reportedly still burning in the aftermath of a series of explosions in China's Tianjin tonight - more than 24 hours after the blasts shook the city.
The country's Xinhua News Agency reported that emergency rescue services were racing against the clock to contain fires in the warehouse district of the city and to find any remaining survivors.
The dramatic moment the Chinese city of Tianjin was shaken by a series of explosions has emerged.
Dan Van Duren captured the blasts on video camera as flames shot up over the city skyline:
At least 50 people were reportedly killed in yesterday's blasts and as many as 700 are believed to have been injured.
More images have emerged today showing the city of Tianjin, China, in the aftermath of a series of huge explosions that killed 50 and injured hundreds more.
An aerial image of the warehouse area in the northern Chinese city of Tianjin shows the scale of the devastation after two huge explosions ripped through the area yesterday.
The country's Xinhua News Agency tweeted a picture shot from above the scene of the explosions showing burnt out building shells and black smoke billowing into the air:
The company which owned the warehouse at the heart of two huge explosions which ripped through a port district in China failed a safety inspection two years ago, local media has reported.
It comes as pictures emerge of the devastation caused by the explosions and fires in Tianjin.
Xinhua News Agency identified Ruihai Logistics as the firm which owned the storage unit - and according to a report posted by the Tianjin Maritime Safety Administration in January last year, five of the 4,325 containers checked at the site failed to meet safety standards.
The main problem was inappropriate 'danger' labelling, the report added, but did not go into further detail on the matter.
Ruihai Logistics describes itself as a government-approved firm specialising in handling "dangerous goods", and had been inspected along with four other companies operating in the region.
Government-backed newspaper China Daily added that the company's manager had been detained by police, though this information has not been independently verified.
Firefighters are still battling to put out the blaze. Officials say until the danger is over, the cause of the blasts - which left at least 50 dead and hundreds more injured - cannot be established.