Salute usage as Firecracker

Solution 1:

From Alexander Hardt, Pyrotechnics (2001), page 184 [PDF]:

The word salute is sometimes used as a generic term for any explosive firework, but is really only correct for one which produces a single loud bang as its only effect. The term is derived from military usage, where, especially in the Navy, a blank cannon load or an exploding rocket was often used as a greeting to friendly forces.

When people in the United States began to build powerful and loud explosives for amateur use in celebrations like the Fourth of July, they applied the name "cannon salute" or simply "salute" to them as well.

A 1905 publication by George Murray, identified as "Inspector of Combustibles," lists, in 152 pages, the Laws, Ordinances and Regulations Governing the Manufacture, Storage[,] Sale and Use of ... Explosives and Combustible Material in the City of New York. Among the banned explosives listed are the following:

(h) Salutes containing chlorate of potash and sulphur.

(i) All bombs or report shells containing chlorate of potash and sulphur in admixture.

(j) All bombs of any description larger than four inches in diameter.

(k) All cannon salutes.

"Cannon salutes" thus were a class of percussion firecrackers so-named because they approximated the report of a blank-filled cannon. Various sources report that these explosives were banned early in the 20th century because they acquired a bad reputation for blowing off hands and arms of inexpert users.

Firecrackers called "salutes" today are (relatively) weak imitations of the powerful, deafening, early-20th-century "cannon salute" firecrackers; but the name has lingered even as cautionary tales of one-armed victims of Fourth of July mishaps have faded.

Solution 2:

From the National Fire Protection Association (NFPA) 1123 (2018):

Chapter 3: Definitions

3.3.39 Salute: Fireworks designed to produce sound as their primary effect

3.3.39.1 Aerial Salute. A salute that functions as an aerial shell

3.3.39.2 Ground Salute. A salute that functions from a stationary or secured position

Solution 3:

I know it's a bit of a stretch, but the word "salute" is very commonly used in Russian as a way to describe fireworks. These are two different things from the technological point of view, and fireworks are usually more spectacular and sophisticated than salutes, but you can always expect a celebratory salute over the Kremlin at the end of a public holiday. The etymology of the Russian word goes back to the naval tradition of one ship greeting (i.e. saluting) another by firing blanks. I'm not sure that it can help your research, but I can hypothesize that in may be a kind of contamination or a borrowing.