How terrible is the explosion of ammonium nitrate？ A cargo ship full of fertilizer blew up thousands of buildings.

Original SME SME technology story

Chemical plant explosions have occurred frequently at home and abroad, which is frightening.

One to two, people have a fear of dangerous chemicals.

But life is always inseparable from chemistry, and even the fertilizer used in the cultivation of essential grain may be explosive and dangerous goods. Ammonium nitrate is a commonly used agricultural fertilizer, but it is also the "culprit" that caused the worst industrial disaster in American history.

Smoke billowing from the explosion in the worst industrial disaster in American history.

This chemical with the word "nitrate" as the head is always disturbing.

Perhaps it is because they are often known together with explosions. For example, trinitrotoluene, the main component of TNT explosives, is made by nitration of toluene.

The great power of TNT has long been recognized. A Grenade thrown on the battlefield killed and injured a large area only contains 50 grams of TNT, and 14 kilograms of TNT can destroy a football field.

As early as the mid-19th century, Swedish engineers applied for a patent to support mixed explosives with ammonium nitrate and other combustion improvers.

Ammonium nitrate has since become a widely used raw material for industrial explosives.

A quarter pound TNT Grenade

Although ammonium nitrate can be used as an explosive, pure ammonium nitrate without combustion improver is actually the most difficult nitric explosive to detonate.

It does not burn by itself at room temperature, and ammonium nitrate is extremely insensitive to impact.

The experimental study shows that the 50kg hammer falls on solid ammonium nitrate from a height of 50cm, and its explosion probability is 0;

Compared with the famous explosive nitroglycerin, a 200g hammer can be detonated 100% when it falls from a height of 20cm.

At the same time, ammonium nitrate has a high nitrogen concentration and stable performance, so people often use it as a nitrogen-containing fertilizer.

Nitrogen fertilizer is mainly helpful to improve the yield and quality of crops.

As everyone knows, ammonium nitrate fertilizer, which made people relax their vigilance, triggered a sudden compound disaster of land, sea and air.

Ammonium nitrate fertilizer

After World War II, although the United States won the war, most areas fell into the post-war economic depression.

However, the southern city of Texas is a different story.

This coastal city is busy day and night, with chemical plants and oil refineries running nonstop, and there are endless cargo ships in the port.

At that time, Texas was praised as a "port of opportunity" by major American media and newspapers, and it was the core of industrial development in the South.

This prosperity made the whole country envy, but soon, the prosperous industrial development also brewed a small Mars that destroyed everything.

By 1947, about 2,500 ships visited the ports in Texas every year, and even Monsanto opened a chemical plant in the town.

On April 16th, the wharf began to operate before dawn as usual, but it was a special day recorded in American industrial history.

There is a cargo ship, the Grand Camp, moored beside the port. This French cargo ship has been staying for five days.

The ship is loaded with some oilfield equipment, drill pipes, hemp ropes and weapons and ammunition shipped from Belgium.

And its main "passenger" is actually 2300 tons of ammonium nitrate fertilizer.

At 8 o’clock in the morning, the crew was carrying the few remaining bags of ammonium nitrate into the cabin, when a smell of smoke caught their attention.

They looked intently and saw that the smoke seemed to be coming from the No.4 cabin where fertilizer was piled up.

Perhaps some ignorant crew member or docker ignored the no-smoking sign and smoked on the ship, which caused the fire.

The fire quickly spread to the deck and hull surface, and the smoke became bigger and bigger.

The crew quickly picked up fire extinguishers and fire pipes to put out the fire, and more than 20 firefighters arrived in time.

Seeing that the fire did not decrease, it became more and more intense, and the crew came up with another fire extinguishing method.

Rescuers stopped using water to put out the fire, but sealed the warehouse with slats and covered it with tarpaulins;

Then the high-temperature steam is introduced into the cabin, and it is intended to squeeze out the oxygen in the cabin in this form.

In this way, without one of the three elements of combustion, combustion can not continue.

This method was a common fire fighting method for cargo ships at that time, and the captain also mixed selfishness in it-reducing the loss caused by the wet goods.

* Note: Material combustion requires three elements: combustion improver, combustible and temperature reaching the ignition point. Among them, oxygen is the most common combustion promoter.

People never expected that this method was really good, but it was equivalent to adding fuel to the fire for the cargo ship transporting ammonium nitrate.

More terrible than the fire of ammonium nitrate is the explosion.

Although ammonium nitrate is resistant to impact, it is very fragile in the face of high temperature.

When the temperature reaches about 165℃ or comes into contact with an open flame, solid ammonium nitrate will rapidly decompose to produce nitrous oxide and water vapor.

Nitrous oxide will also be converted into oxygen at high temperature, and the gas that rescuers tried their best to remove reappeared.

At this time, the reaction brewing in the air is not just as simple as burning.

The high temperature and high pressure environment created by firefighters made the warehouse a closed container to accelerate the explosion reaction.

People didn’t know anything about it at that time, only to find that even with powerful rescue forces, the fire was still too big to control.

At 8: 30, the captain ordered to abandon the Grand Camp and bear the loss of all the goods.

However, he was only distressed to lose a ship and cargo, but he didn’t expect the fire to turn into a bigger disaster.

At 9: 12, a loud bang from the port made almost the whole city tremble.

A fireball went straight into the sky and turned the sky red. Thick smoke soared to an altitude of 610 meters and spread everywhere. Part of the hull melted into pieces and jetted out of the dock.

Two planes accidentally flew over at this time and were directly destroyed and fell.

The explosion near the wharf caused the 160km water body in Fiona Fang to be choppy, which triggered a tsunami, and set off waves as high as 4.5m, hitting the land.

Even Houston, 40 kilometers north of Texas, felt a violent vibration, and the window glass of some houses was directly shattered.

This has become a major disaster facing the sea, land and air in all directions.

In the sudden explosion, none of the first firefighters who entered the rescue survived.

Nearby residents took refuge at home with trepidation, but they still could not escape the surging tsunami.

The fire that continues the explosion is still going on, which makes people afraid to get close.

The busy Texas dock is not a harbor of the Grand Camp, but dense cargo ships and chemical plants and refineries along the coast have become another hidden danger.

Just 15 hours after the explosion, people have not recovered from it, and the second explosion happened.

A large number of chemical plants and refineries are densely distributed.

On the coast 200 meters away from the Grand Camp, there is also a cargo ship named Success.

This cargo ship also contains nearly 1000 tons of ammonium nitrate and 180 tons of sulfur.

The explosion and fire extended to the USS Success, bringing a second thrilling explosion.

The explosion triggered a series of chain reactions, and nearby freighters and factories exploded one after another.

Successive disasters eventually killed 581 people and injured more than 3,500 people. At that time, more than a quarter of the population in Texas was killed or injured in the disaster.

Thousands of residential buildings and commercial buildings were destroyed by the tsunami, and 1,100 docks were damaged.

At that time, the prosperous capital and industrial city of Texas lost about $100 million (equivalent to more than $1 billion now).

This is the worst disaster in American industrial history, and the reasons behind it are complicated and strange.

First of all, there was a small fire in the cabin for reasons that have not been clear so far.

Then rescuers used self-defeating fire fighting methods, which eventually aggravated the explosion.

At the same time, the government regulatory agencies themselves have many loopholes.

In the era of post-war economic recovery, the industrial process has become the most important thing beyond laws and policies, and managers can only ignore the interests.

After the accident, a large-scale funeral was held for the unidentified victims.

At that time, there were about 6,000 fertilizer chemical plants in the United States, but most of them did not report the storage of ammonium nitrate in the Department of Homeland Security, although the inventory was as high as 1,300 times that of the mandatory review.

It is conceivable that the industrial intensive Texas was equivalent to hiding countless stealth bombs at that time, just waiting for an opportunity to detonate.

Once detonated, it will lead to irreparable loss of life and property.

Only in this way can the federal government face up to the audit and supervision of chemical plants and dangerous chemicals.

The government has drawn up new standards and improved the management and transportation system of dangerous chemicals. Enterprises have also established an industrial mutual aid system, and agreed to join hands in the event of danger.

This appalling Texas explosion has become history, and the United States has entered a new era of strict industrial management.

Afterwards, major media rushed to report the accident.

But no matter what era the strict system is put in, there will always be people who exploit loopholes.

Dangerous chemicals such as ammonium nitrate are never kind to those who neglect them.

In 2013, also in Texas, another chemical fertilizer factory exploded.

However, this time, it was no longer because of people’s ignorance that the mistake was made, but the chemical fertilizer plant built a non-compliant ammonia storage tank privately.

Up to 24 tons of anhydrous ammonia accidentally triggered an explosion, killing 35 people.

Sadly, some people were killed innocently in the explosion of ammonium nitrate, and some people deliberately used ammonium nitrate as a weapon for terrorist attacks.

In 2011, a nightclub in Bali exploded. This is a vicious explosion in which 202 people were killed by terrorists using ammonium nitrate.

In 1995, terrorists used ammonium nitrate to make explosives to blow up the federal building.

Chemicals usually have both advantages and disadvantages for human beings.

Ammonium nitrate is a common industrial explosive, but it is also a good fertilizer.

Nitroglycerin, which can be used as an explosive, is also a good medicine for cardiovascular diseases …

People often suffer while using them to achieve certain interests.

However, the progress of human beings lies in that no matter how dangerous the substance is, it can be controlled by human beings and finally serve human beings.

Ammonium nitrate. Wikipedia, June 26, 2019.

MarcLallanilla, LiveScience. What Causes Fertilizer Explosions? ScientificAmerican, 2013.04.18.

1947 TexasCity Disaster. Moore Memorial Publiclibrary.

MichaelBaumann. How a Fertilizer Accident Led to the Deadliest Industrial Disaster inAmerican History. The Ringer, 2017.08.24.

SteveOlafson. The Explosion: 50 Years Later, Texas City still Remembers/’Texas Cityjust blew up’/A powerful chemical explosion 50 years ago propelled a small porttown into an unwelcome national and world spotlight. Chron, 1997.04.13.

Original title: "How terrible is the explosion of ammonium nitrate? A cargo ship full of fertilizer blew up thousands of buildings.

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