Sean Penn is now at the center of a National Labor Relations Board complaint that alleges the actor threatened employees who criticized the working conditions of a vaccination site he helped set up in Los Angeles. After two employees took to a New York Times message board to blast the Penn effort, the actor sent out a 2,200-word diatribe slamming those who dared challenge him. “And to whoever authored these, understand that in every cell of my body is a vitriol for the way your actions reflect so harmfully upon your brothers and sisters in arms,” Penn wrote. The letter found its way to an L.A. lawyer, who brought it to the attention of the labor board, which has filed a complaint against Penn and his organization. The lawyer claimed Penn’s angry missive “amounted to coercive conduct.” In a statement to the Los Angeles Times, Penn said the complaint lacked “legal merit” and he “completely stands by his email.”