 Congress gave the CSB a unique statutory mission and provided in law that no other agency or executive branch official may direct the activities of the Board.Following the successful model of the National Transportation Safety Board and the Department of Transportation, Congress directed that the CSB's investigative function be completely independent of the rulemaking, inspection, and enforcement authorities of the Environmental Protection Agency and Occupational Safety and Health Administration.Congress recognized that Board investigations would identify chemical hazards that were not addressed by those agencies.