The United States Senate Select Committee on Improper Activities in Labor and Management was a select committee created by the United States Senate on January 30, 1957, and dissolved on March 31, 1960. The select committee was directed to study the extent of criminal or other improper practices in the field of labor-management relations or in groups of employees or employers, and to suggest changes in the laws of the United States that would provide protection against such practices or activities. It conducted 253 active investigations, served 8,000 subpoenas for witnesses and documents, held 270 days of hearings, took testimony from 1,526 witnesses (343 of whom invoked the Fifth Amendment), and compiled almost 150,000 pages of testimony. At the peak of its activity in 1958, 104 persons worked for the committee. The select committee's work led directly to the enactment of the Labor-Management Reporting and Disclosure Act (Public Law 86-257, also known as the Landrum-Griffin Act) on September 14, 1959. As part of its investigations into Mafia activities, the Teamsters, and organized labor in general, evidence was unearthed of a mob-sponsored plot in which Oregon Teamsters unions would seize control of the state legislature, state police, and state attorney general's office through bribery, extortion and blackmail. The committee was chaired by Senator John Little McClellan, a Democrat from Arkansas.