The letter led by Senator Richard Blumenthal, a Democrat, to CEO Elon Musk cited numerous incidents of racial and sexual harassment as well as complaints about Tesla's vehicles and its Full Self-Driving Beta software.

"We are deeply concerned that the arbitration agreements you impose on your workers and consumers have kept these reportedly deplorable and discriminatory conditions and potential safety flaws from the public eye and limited regulatory authorities' ability to protect Tesla customers and employees and hold Tesla publicly accountable," the letter said.

(Reporting by David Shepardson; Editing by Mark Porter)