Thousands of escaped slaves, known as Contraband, followed the Union army to Helena in July 1862, and within weeks the army put hundreds of them to work building Fort Curtis. African American laborers moved tons of earth, cut trees, milled lumber, and performed the hard labor required to build a fort larger than the reconstruction in three months, using only shovels, picks, and wheelbarrows during the hottest months of the year. Union soldiers also seized African American men, including some already working for the army in other jobs, and forced them onto the project. General Eugene A. Carr, who advocated for the Contraband, protested to General Curtis that such seizures should go through proper channels and warned that these actions undermined any sense of security for those who had entered the army's service in good faith. Despite being forced to labor on the fort, many of the men who built Fort Curtis enlisted in the Union army the following spring.