The Occupational Safety and Health Administration (OSHA) has updated its guidance on workplace violence. The General Duty Clause requires employers to provide a workplace free from recognized hazards likely to cause death or serious physical harm to employees. Directive Number CPL 02-01-058, “Enforcement Procedures and Scheduling for Occupational Exposure to Workplace Violence” —which became effective on January 10, 2017 — addresses when hazards created by people (i.e., violent coworker, customer, etc.) violate the General Duty Clause.

You can read the Directive here: https://www.osha.gov/OshDoc/Directive_pdf/CPL_02-01-058.pdf