Massive Explosion in Tianjin

[Exonerate]

BBC:

Massive explosions have hit China's northern port city of Tianjin, leaving at least seven people dead and hundreds more injured.

State media said the blasts happened in a warehouse storing "dangerous and chemical goods" in an industrial area of the city.

Pictures and video on social media showed flames lighting up the sky, and buildings are said to have collapsed.

Hospitals are reported to be overwhelmed with casualties.

The editor of the BBC's Chinese Service, Raymond Li, says all indications are that it is an industrial accident.

State broadcaster China Central Television (CCTV) said a shipment of explosives had detonated but this was not confirmed.

The first explosion at about 23:30 (16:30 GMT) was followed by another seconds later. Shockwaves were felt several kilometres away.

The China Earthquake Networks Centre said the magnitude of the first explosion was the equivalent of detonating three tons of TNT, while the second was the equivalent of 21 tons of the explosive.

Further blasts were subsequently triggered nearby, Xinhua state news agency said.

Hours later, fires were still burning and 100 fire engines were at the scene, reported CCTV.

It added that police were focusing on search and rescue operations rather than putting out the fire, as they want all chemicals to burn up completely. There was concern that high winds in the area could cause another blast.

Two firefighters were "out of contact", and four were among the injured, Xinhua said.

One witness, named only as Ms Yang, told local media she was out shopping when "suddenly from behind there was a big fireball and explosion".

"At the time of the explosion the ground was shaking fiercely, nearby cars and buildings were shaking, a few buildings' glass all broke and everyone started to run," she said.

"Now all the residents are gathered in the street."

Another witness, Canadian teacher Monica Andrews, told how she woke in panic after what she thought was an earthquake.

"I... looked out the window and the sky was red. I just watched a second explosion go off and [it was] just pure chaos, everyone leaving their apartment buildings thinking it's an earthquake, cars trying to leave the complex. It was crazy," she told the BBC.

China National Radio said cracks were visible in buildings near the site of the blast.

Several tower blocks near the port area are without power, CCTV said.

The blasts took place in a warehouse area storing dangerous goods in Tianjin's Binhai development zone, Xinhua said.

Tianjin, home to some 15 million people, is a major port and industrial area to the south-east of the Chinese capital, Beijing,

Jesus. 21 tons is quite a bit, here's hoping they had good zoning laws in the area. Casualty counts still rolling in, hopefully there will only be a few hundred dead.

[Sea Skimmer]

One of many complied videos
https://www.youtube.com/watch?v=eHdq_yxnj3o

21 tons is surely an understatement, an open air blast won't couple anything like its full force into the ground, or even a lot of it, and any estimation based on the actual measured earth shock is going to be highly inaccurate without knowing what sort of material actually exploded.

Very lucky this was at night with I hope, few people working in the port. This looks like it was at least several times larger blast then that figure, anyone within five hundred meters is probably dead.

[Exonerate]

Apparently the conversion method assumes an underground explosion... I don't suppose anybody knows offhand what proportion of energy typically goes into the ground?

Secondary explosions still occurring sporadically, firefighting efforts have been suspended due to uncertainty over the contents of nearby warehouses.

[Sea Skimmer]

50+ fire fighters known dead or missing now.

The drone footage of the diaster is well, enough is blown up you can't even tell where the exact origin was, but you can see whole shipping containers dropped by the blast onto the freeway are apparently not a reason to close an elevated freeway in China.

[Enigma]

24 tons? *whistles* I take it they were not found of safety measures to prevent stuff like this?

[Sea Skimmer]

Apparently the conversion method assumes an underground explosion... I don't suppose anybody knows offhand what proportion of energy typically goes into the ground?

It varies. Such as, being a port area with stacks of shipping containers the ground would be a very thick concrete slab, which is very effective at deflecting shock/blast energy. On the other hand if the explosion took place at the bottom of a stack of containers, the containers above owuld be massive enough to tamp the blast into the ground. Worst case though the true yield could be 700% of the registered ground shock of a purely underground explosion. 2-4 times is a lot more likely though judging by the damage.

24 tons? *whistles* I take it they were not found of safety measures to prevent stuff like this?

Honestly while its probable someone screwed up a lot, even in the west some rather large shipments of explosive substances are still allowed. A single railcar of ammonia nitrate could yield this kind of explosion, but only after being involved in a major fire involving high temperatures without the chemical being burned off in the process. A damn lot of safety is on the basis of minimizing transit time and avoiding ignition sources, rather then actually precluding major explosions completely as far as the 'tens of tons' range goes. However this logic all falls apart if nobody knows to instantly evacuate a mile radius upon the outbreak of any level of fire. The reallllly high yield stuff like Texas City in 1947 is now avoided by isolating the storage containers and loading points completely. Even in China I think they have that part of life covered. This was big, but not on par with past disasters like the Black Tom explosion (which may have been sabotage anyway) or said Texas City blast.

In this case we had a report of fire, then a ripple of small explosions which were probably drummed chemicals going up, then a large explosion, and then the entire area consumed in a mass detonation. It may well have been that any one material on site was safe, and not a mass explosion risk on its own, but the collective combination was utterly lethal. This is how the Bombay explosion in 1944 occurred, and that Iranian train disaster a decade ago.

[Broomstick]

Jesus. 21 tons is quite a bit, here's hoping they had good zoning laws in the area.

Um... in China? They do have something of a reputation for playing fast and loose with safety by Western standards.

Though to be fair, there are things/quantities of stuff shipped all over the world that have the potential for great mayhem.

[Exonerate]

Lots of rumormongering right now, claims of hundreds of bodies being recovered, thousands displaced for now. There were concerns about chemical residue and fumes (Sodium cyanide), the PLA sent in a ~200 person NBC team to help with the cleanup.

Firefighters first responded to a fire at the warehouse. According to local police, ammonium nitrate, potassium nitrate and calcium carbide were present - calcium carbide reacts to water and releases acetylene, which is an explosive gas, so it's possible that set off a chain reaction to detonate the ammonium nitrate. They really ought to have had something more suitable for chemical fires on hand.

Um... in China? They do have something of a reputation for playing fast and loose with safety by Western standards.

Though to be fair, there are things/quantities of stuff shipped all over the world that have the potential for great mayhem.

Tianjin is the 10th largest port in the world and pretty close to Beijing, so I thought they'd keep a closer eye on it there. Even in China somebody must've paused for a moment to consider the safety implications. There's apparently a law on the books to keep chemical storage warehouses at least 1km from residential buildings and public transportation, but in this case, an apartment complex was only 600m away. My bet is that heads are going to roll over this incident, possibly literally.

[madd0ct0r]

I'd rank acetylene a bit higher then an explosive gas - it's used for welding underwater, since it burns that hot.

[Thanas]

Reports in the west suggest that many of the deaths might have been firemen because they were allegedly fighting the fire when the explosion occurred and thus were well within the blast area.

[Broomstick]

Tianjin is the 10th largest port in the world and pretty close to Beijing, so I thought they'd keep a closer eye on it there. Even in China somebody must've paused for a moment to consider the safety implications. There's apparently a law on the books to keep chemical storage warehouses at least 1km from residential buildings and public transportation, but in this case, an apartment complex was only 600m away. My bet is that heads are going to roll over this incident, possibly literally.

1 km is not sufficient distance for that sort of hazard.

And, given the blast, heads might have already literally rolled, but not for the reasons you allude to.

[Simon_Jester]

Well, as I understand and envision it...

One kilometer is far enough that you can at least realistically hope the explosion won't pulverize whole buildings and so on. That saves millions in property damage in case of a massive explosion. Plus, a kilometer is pretty good safety against the sort of relatively 'small' explosions that normally happen on short notice.

Larger explosions are usually the result of a major fire breaking out in an area containing explosive substances, so there's time to evacuate people to a greater distance.

For true safety you want to evacuate people to a much greater distance, of course, because debris flies a long way... but in the event of an emergency you're likely to have more time to do it, and people are going to have a much better chance of survival if they remain a kilometer or more away, even if they're not two kilometers away.

Whereas when inhabited buildings are located within, oh, several hundred meters... those people have a whelk's chance of survival in a supernova if things blow up, and even evacuating them is very hazardous because you have to get into that no-survivors distance to do so.

[Sea Skimmer]

The whole area was only really developed in the last odd decade, and going back in the Google Earth history, it seems when the facility was first built the nearest apartment buildings actually were just about 1km away. But then a whole new closer development sprung up on land which was still swamp at that point. Soooo it may well be that the owners complied with planning law, but other people didn't. As recently as 2004 half the land area of the port complex didn't even physically exist, they were still building the breakwaters to contain the planned landfill. Even by Chinese standards the development is massive. Figures though because this is the main port for all of Manchuria, and politics have held back Chinese attempts to build facilities in North Korea and Russia.

Anyway if you don't follow reasonable quantity-distance standards for hazmats no feasible amount of standoff is in an urban area is ever going to be safe. But nobody in the world segregates chemicals that aren't outright high explosives/heavy caliber ammunition completely.

[Sea Skimmer]

So.... over two days after the explosion, China just ordered a 3km radius evacuated around the blast zone because they confirmed what had been rumored online the first night of the blast, the site was storing bulk cyanide! Though in the scheme of things, the human body can rapidly eliminate cyanide so sub lethal exposure is actually all that bad for anyone. Good thing the blast cloud blew right out to sea though.

Also one man found alive within 50 meters of the epicenter. Go shipping containers as armor.
http://www.bbc.com/news/world-asia-china-33945293

[Sea Skimmer]

160ft scale crater blown into a heavy concrete slab.

[Venator]

For perspective: https://i.imgur.com/ucsa3dV.jpg

Reddit has some very creative ideas about what's actually IN the crater, but the most reliable info I can find is that a lot of it is run-off of water used in the firefighting effort.

[Sea Skimmer]

Wow so all those morons on Reddit just missed the large drainage ditch that runs right alongside the site? How many thousands of posts did it take? I'm sure they missed that this was swamp being land filled less then a decade ago.

The answer is very simple. The entire area is landfill, very recent landfill at that, of extremely low lying coastal bog. It has flooded because that is the actual level of the groundwater due to proximity to the ocean ect... It is incredibly common for bomb and impact craters to flood from this.

[Simon_Jester]

Also one man found alive within 50 meters of the epicenter. Go shipping containers as armor.
http://www.bbc.com/news/world-asia-china-33945293

I hereby award this man the Tsutomu Yamaguchi Memorial "Holy Shit Nobody Could Survive That, I Survived That Anyway" award for 2015.

[Andras]

interesting article

http://www.bangkokpost.com/opinion/opin ... -warehouse

[SpottedKitty]

interesting article

http://www.bangkokpost.com/opinion/opin ... -warehouse

I remember reading a comment on BBC news the other day that the houses were built recently, the warehouses had been there much longer.

Didn't something similar happen a few years ago in the US? A commercial fertiliser distributor had their storage tanks blow up spectacularly, but over the years since the storage yard was built, the nearby town had grown out to pretty much surround the place. A smaller explosion IIRC, but the completeness of the destruction in the town was very similar.

[Broomstick]

It's a chronic problem with airports the world over - they're built away from buildings and most especially homes, then things get built up around them. When the inevitable take off or landing goes bad everyone expresses surprise at the danger inherent in aviation.

And yes - also factories, storage facilities, smelters, etc.

[Darmalus]

Happens a lot with airports too. Airport gets built a safe distance away in the middle of farmland where nothing but crops would get smashed by a crash, then people build high rises all around it.

Edit: Beaten to the punch!