A case is work-related any time an event or exposure in the work environment either causes or contributes to an injury or illness or significantly aggravates a pre-existing injury or illness, unless one of the exceptions in 1904.5(b)(2) applies. The work environment includes the establishment and other locations where one or more employees are working or are present as a condition of their employment. The case in question would be work-related if the employee was injured as a result of an event or exposure at work, regardless of whether the injury occurred after normal work hours.