The factory was the city's largest garment manufacturer, making "shirtwaist" blouses, as many as 500 workers, working from 7:30 a.m. to as late as 9 p.m. during the busy season, six days a week, earning between $1 and $12 an hour. On average, wages seem to have been somewhere in the neighborhood of $3.00 to $3.50 an hour in today's dollars, inflation-adjusted.
A grimly fascinating "oral history" of former worker Pauline Newman can be found at History Matters, including audio. Here's an excerpt:
They were the kind of employers who didn't recognize anyone working for them as a human being. You were not allowed to sing. Operators would like to have sung, because they, too, had the same thing to do, and weren't allowed to sing. You were not allowed to talk to each other. Oh, no!
They would sneak up behind you, and if you were found talking to your next colleague you were admonished. If you'd keep on, you'd be fired. If you went to the toilet, and you were there more than the forelady or foreman thought you should be, you were threatened to be laid off for a half a day, and sent home, and that meant, of course, no pay, you know? You were not allowed to use the passenger elevator, only a freight elevator.
And ah, you were watched every minute of the day by the foreman, forelady. Employers would sneak behind your back. And you were not allowed to have your lunch on the fire escape in the summertime. And that door was locked. And that was proved during the investigation of the fire. They were mean people.
A 1909 strike at Triangle Shirtwaist, in which Ms. Newman had taken part, ended in failure. At the time of the fire, stairway doors in the 10-story building remained locked to prevent theft. The fire escape was defective. The owners, successful Jews who had emigrated to America only 20 years before the tragedy, escaped via the roof.