The First Labor Day Having the first Monday in September off from work was significant for American workers in 1894, when Labor Day was declared a national holiday. Working conditions in the country’s factories, railroads, mills, and mines were grim. Employees, including many children, were often required to work 12 hours a day, six days a week, in crowded, poorly ventilated spaces. Supervision was harsh and punishments were handed out to those who talked or sang as they worked.