"U.S. aircraft dropped more ordnance on Laos than on all countries during World War II, leaving Laos with about 78 million pieces of unexploded ordnance (UXO) by the end of the war." How is this possible?

by envatted_love

Wikipedia:

The U.S. dropped 2,756,941 tons of ordnance on 113,716 Laotian sites in 230,516 sorties between 1965 and 1973 alone. By September 1969, the Plain of Jars was largely deserted.

U.S. aircraft dropped more ordnance on Laos than on all countries during World War II, leaving Laos with about 78 million pieces of unexploded ordnance (UXO) by the end of the war. Casualties continue to mount from UXO dropped by the U.S. and Laotian Air Forces from 1964 to 1973. It has been reported that, between 1964 and 1973, areas controlled by the invading communist North Vietnamese and Pathet Lao were hit by an average of one B‑52 bomb-load every eight minutes, 24 hours a day. Xiangkhouang Province was the most heavily bombed province. Thirty percent of bombs failed to explode immediately.

The citation for the 78 million is to this PDF: Khamvongsa, Channapha; Russell, Elaine (2009). "Legacies of War: Cluster Bombs in Laos"

This is jaw-dropping, and raises many questions.

  1. Was a 30% failure-to-explode rate considered normal? How did this rate compare to rates in previous decades (e.g., WW2) or later ones (e.g., Persian Gulf War)?

  2. Is the figure of 78 million unexploded bombs a widely accepted estimate?

  3. Given some calculation (see below), and assuming the numbers in the quoted passage are accurate, we can infer either (a) a low number of planes per mission along with a high number of bombs per plane (like 5 & 226), (b) a high number of planes per missions along with a low number of bombs per plane (like 200 & 6), or (c) somewhere between the two. Which is closest to the truth?

Calculations

To bastardize the Drake equation, to achieve u = 78 million unexploded bombs we can multiply together:

  • Number of missions m: 230,516 (over nine years this implies 70/day on average)

  • Average number of planes per mission p: ?

  • Average number of bombs per plane b: ?

  • Probability that a bomb will fail to explode f: 30%

The two parameters to be estimated bear the relationship b = u/(m*p*f), or, equivalently, p = u/(m*b*f). Plugging in the known values of u, m, and f, we have:

  1. b = 78,000,000 / ( 230,516 * p * 30%)

  2. p = 78,000,000 / ( 230,516 * b * 30%)

In other words, allowable pairs of b and p include:

Planes/Mission Bombs/Plane
10 113
20 56
30 38
40 28
50 23
60 19
70 16
80 14
90 13
100 11

Thanks!

P.S. I see that adjacent questions have been asked previously (e.g., here and here), but don't quite touch what I'm looking for.

Edit: formatting

restricteddata

The article you linked to says it is more like 580,344 sorties over 9 years (see Table 1). It is also worth noting that what are being discussed specifically are cluster bombs: bombs that contain lots of small "bomblets." Each bomb can release 600-700 bomblets. The counts of unexploded munitions are bomblets. This video gives you a sense of how these looked when being released. In this video, you have one plane releasing too many bombs for me to count — I started counting the large releases from the first plane and got to over 20 of them. Each of them then breaks into what could be hundreds of bomblets.

So I think your overriding assumption, that this is a WWII-style "many planes, many bombs" approach, is entirely wrong. This is likely a "few planes, stupendous number of bombs per plane" situation.

I suspect that the poor failure-to-detonate rate is related to the cluster munition itself. They were crude little mass-produced devices, being scattered (as the footage makes clear) over a large area at high speed.