Final answer:
The careless stacking of boxes that leads to them falling on a coworker is a human factor hazard classified as substandard practice, emphasizing the importance of following safety protocols.
Step-by-step explanation:
Careless stacking of boxes such that the boxes later fall on a coworker would be classified as a type of hazard known as human factor—substandard practice. This category of hazard refers to the unsafe procedures or failure to follow established safety protocols, which can lead to accidents in the workplace. It is essential for employees to adhere to safety guidelines to prevent such accidents.