The entire story hangs on the fourth word from the end; you can search for it and read it. The short story, 5600 words, details a World War II factory worker. Here is part of a paragraph:
Paulette, who worked with an electric arc, never
tired of watching this woman adjust her torch.
When she lit it, the flame was white inside but surrounded by a yellow
envelope that sent up twisting columns of smoke. Then she changed the mixture and a plug of
intense white appeared at the end of the torch, in the center of a small orange
flare. When finally she got her neutral
flame—with a tighter white plug, a colorless core, and a sapphire-blue
casing—she lowered her mask and bent over the work.