linked - Investigating the Terror

Q. And if you're not working in a scientific laboratory, what effect
would that have on the yield?
A. It's drastically reduced. You're going to have a lot of spillage
because you're going to be cautious. It will splash out. You will
lose some of the mixture on the ground. You're going to lose
some because it's getting held up in your filter paper and that's
a pretty good amount. So, in reality, in a non-laboratory
environment, I would expect that and, as a matter of fact, you
would get somewhere around a 60- to 70-percent yield.
Williams then testified:
With 1,500 pounds ordered and delivered of urea to the storage
area, and finding 300 pounds left in that shed, mixing it with the
quantities of nitric acid, the urea and nitric acid would form
ideally about 90 percent of the gross weight.
So, if we have 1,200 pounds of urea used unaccounted for, if it
was used, we could make a mixture of somewhere around 2,100
pounds, give or take, on ideal conditions of urea nitrate. If the
urea nitrate was mixed in a less than ideal environment, not
laboratory techniques, and using something as simple as
newspaper for filter paper, I would expect that we would get in
the neighborhood of somewhere between 1,200 and 16, 1,800
pounds of urea nitrate and then depending on how it was
packaged, how sloppy the individual or individuals were that
were packing it, you might lose a few more pounds.
So, in essence, you could have an explosive charge of urea
nitrate perhaps between 1,200 and 16, 1,800 pounds.
Later in his testimony Williams referred to the amount of urea nitrate that
could have been made as about 1,200 pounds.
d. Analysis