I think a Burner is similar to a Welder but they use a different kind of torch and handle different parts of the construction. I'm not very informed on the subject though.
I can provide some context: what she is holding is an oxy/fuel torch that uses pure oxygen and a fuel gas (propane or acetylene typically) to “burn” a hole in the steel plate. Fun fact, the fuel gas is only there to start the cut and preheat the metal, the actual cutting is done by a high pressure stream of oxygen that actually burns the molten steel and ejects it out the bottom of the cut, this process can cut through 12 inches or more of solid steel plate.
It looks like she is working in a prefabrication area where they would cut and weld the steel components before they are installed in whatever they were building at the time, most likely a liberty ship if I were to guess. Nowadays the task of burning these steel plates is automated, with large CNC machines with multiple torches on them cutting up the steel plates, although there is still quite a bit of cutting done by hand, especially in ship repair.