The National Iron & Steel Heritage Museum
Long Days
The steel making process required continuous operation, 24 hours a day, 7 days a week. The simplest method of achieving this was to operate two shifts of 12 hours each. These long days were exhausting and health­hazardous and they disturbed family life at home, with men unable to spend time with their wives and children. 12-hour days were common in most early industries.

Photograph: Steel Mill Workers, Sparrows Point, MD, 1940 — Library of Congress