To allay concerns about the design of the New York and Brooklyn Bridge, Roebling set up a "Bridge Party" in March 1869, where he invited engineers and members of U.S. Congress to see his other spans. Following the bridge party in April, Roebling and several engineers conducted final surveys. During the process, it was determined that the main span would have to be raised from above MHW, requiring several changes to the overall design. In June 1869, while conducting these surveys, Roebling sustained a crush injury to his foot when a ferry pinned it against a piling. After amputation of his crushed toes, he developed a tetanus infection that left him incapacitated and resulted in his death the following month. Washington Roebling, John Roebling's 32-year-old son, was then hired to fill his father's role. When the younger Roebling was hired, Tammany Hall leader William M. Tweed also became involved in the bridge's construction because, as a major landowner in New York City, he had an interest in the project's completion. The New York and Brooklyn Bridge Company—later known simply as the New York Bridge Company—was actually overseen by Tammany Hall, and it approved Roebling's plans and designated him as chief engineer of the project.