On May 12, 1902, the anthracite miners voting in Scranton, Pennsylvania, went out on strike. The maintenance employees, who had much steadier jobs and did not face the special dangers of underground work, walked out on June 2. The union had the support of roughly eighty percent of the workers in this area, or more than 100,000 strikers. Some 30,000 left the region, many headed for Midwestern bituminous mines; 10,000 men returned to Europe. The strike soon produced threats of violence between the strikers on one side and strikebreakers, the Pennsylvania National Guard, local police, and hired detective agencies on the other.