Unions formed in response to unsafe working conditions, low wages, and child labor during the Industrial Revolution. Early union efforts like strikes by steel and coal workers had some success improving conditions. Major unions included the Knights of Labor, AFL, and ILGWU. The 1911 Triangle Shirtwaist Fire, which killed 146 garment workers, highlighted continuing risks. Ultimately, unions achieved safer workplaces, reduced hours, child labor limits, and expanded public education.