I was watching a video just last night that mentioned the Grandcamp explosion in Texas City to be the largest non-nuclear explosion.

The Texas City disaster was 16 April 1947, which would be after the development of nuclear weapons (circa 1945).

Ah, misread the quote there.

Comparing the Texas City explosion with the Halifax explosion may be controversial.
The total amount of fertilizer on-board the Grandcamp had more explosive power than the Halifax explosion.
In one entry Wiki estimates the total potential explosive force of the Grandcamp as 3.2 kilotons of TNT, but the entire cargo did not explode.
There are reports of bags of fertilizer being blown skyward in the Grandcamp explosion.
Further in the same entry, Wiki estimates the Grandcamp explosion as equivalent to 2.7 - 3.2 kilotons of TNT.
The Halifax explosion was estimated as equivalent to 2.9 kilotons of TNT
Comparing the force of the Halifax explosion with the estimated force of the Grandcamp explosion;
Too close to call.
"I was watching a video just last night that mentioned the Grandcamp explosion in Texas City to be the largest non-nuclear explosion."
When reporting events as the "Largest", Biggest", "Best", etc. American news often omit the disclaimer; "In the United States."

As for the biggest non-nuclear explosions:
1. Minor scale;

Quote (https://en.wikipedia.org/wiki/Minor_Scale)

Minor Scale was a test conducted..............involving the detonation of several thousand tons of conventional explosives to simulate the explosion of a small nuclear bomb.
Minor Scale was reported as "the largest planned conventional explosion in the history of the free world"
.........equivalent to 4 kilotons of TNT

2. Misty Picture; A similar test to Minor Scale, equivalent to 3.9 kilotons of TNT

3. Heligoland/British Bang test, equivalent to 3.2 kilotons of TNT
Note: The previous three explosions were after the development of nuclear weapons.

4. Halfax Harbour, equivalent to 2.9 kilotons of TNT.

5. Grandcamp Texas City, equivalent to 2.7+ kilotons of TNT.

Quote (https://en.wikipedia.org/wiki/Largest_artificial_n...)

Comparison with large conventional military ordnance:
The most powerful non-nuclear weapons ever designed are the United States' MOAB (standing for Massive Ordnance Air Blast, also nicknamed Mother Of All Bombs, tested in 2003 and used on April 13, 2017, In Achen Province, Afghanistan) and the Russian Father of All Bombs (tested in 2007).

The Halifax or Grandcamp explosions were each about 66 times more powerful than the Russian Father of All Bombs and 260 times more powerful than the US Mother of All Bombs.

Bill
--------------------
"Why not the best?"
Jimmy Carter

A smaller, but nonetheless spectacular explosive demolition of Ripple Rock in Seymour Narrows near Campbell River, BC in 1958. 1400 tons of Nitramex explosives in tunnels burrowed under the rock - a navigation hazard. Link: http://www.crmuseum.ca/ripple-rock

The part that gets to me most is the railroad telegraph operator who tapped out warning messages rather than seek shelter from the blast he knew was imminent.

I remember Ripple Rock.
A lab tech at the Government Agricultural Research Center in Summerland and myself tried to capture a reading on a homemade recorder.
We built a rig with a boom made out of balsa wood with a stylus riding on a jury-rigged rotating graph.
We mounted the rig at right angles to the direction to Ripple Rock on the cement pier of a railway bridge on the edge of a canyon. The concrete pier was set directly on basaltic bed rock.
At the last minute we anchored a piece of paper and hung a string from a bridge member. The end of the string was weighted and had a pencil riding on the paper.
We were about 250 miles east of the Rock.
We did not detect a quiver.
All we accomplished was to miss the live TV coverage.
We had fun, nonetheless.

Bill
--------------------
"Why not the best?"
Jimmy Carter

Thanks for the Ripple Rock story, Sawbux.

STF

I'm confused.. I thought the Halifax Explosion was from a fire in a bulk freighter filled with ammonium nitrate and in an attempt to put it out they sealed the hatches and fed live steam into the hold which just ran the cargo up to ignition energy. But now I'm seeing reading it was an ammo-ship accident...

Keith Cress
kcress - http://www.flaminsystems.com

Google is your friend https://en.wikipedia.org/wiki/Texas_City_disaster in 1947.

Very similar in its effect on the ship's structure, scattering it a great distance.

Hi Keith;
Halifax; munitions
Texas City; Freighter Grandcamp, 30 years later in 1947 was the fertilizer and steam disaster. Very nearly the same explosive energy. (Too close to call.)

Bill
--------------------
"Why not the best?"
Jimmy Carter

Ah ok. Thanks gents. That's the Texass City mentioned above. Now if I can get that reprogrammed in my head.

Keith Cress
kcress - http://www.flaminsystems.com

The telegrapher / train dispatcher was named Vince Coleman. Thankfully he's been reasonably well remembered for his sacrifice.
"Hold up the train. Ammunition ship afire in harbour making for Pier 6 and will explode. Guess this will be my last message. Good-bye boys."

This 'Sixty Symbols' (a series) video includes a listing of the cargo on the SS Mont-Blanc; that aspect is quite interesting.
https://www.youtube.com/watch?v=u5uTAt_A8BY
(Very minor tidbit, she spelled "Dartmouth" incorrectly.)

To me, one of the amazing things was that the collision that the Mont Blanc had with the Imo was actually pretty gentle, not much more than a bump. But it tipped over some barrels containing flammable liquid (benzol?) which caught on fire due to sparks.
It's like having a shopping cart roll into your automobile in the parking lot and having your car explode.

Thank you for the remembrance of Vince Coleman, VE1BLL.
I was not aware of his sacrifice.

Bill
--------------------
"Why not the best?"
Jimmy Carter

Check this out - 3D animated story of the event: http://newsinteractives.cbc.ca/halifaxexplosion/

STF

I was completely unaware of this disaster but heard several references to it over the weekend. ET was first.

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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

Forget the above reference to theRussian "Father of all Bombs" ....

Chemical weaponry is for losers.

The Ruskies detonated the "Tsar-bomb", or "King of bombs". It was tested on 30 October 1961 and remains the most powerful human-made explosion in history.

50 megatons of TNT equivalent

https://en.wikipedia.org/wiki/Tsar_Bomba

MJCronin
Sr. Process Engineer