An in depth study was undertaken of factors associated with accidents during the use of stairways at the workplace. Attempts were made to identify the industries with the highest accident rates on stairs and to identify predisposing factors and events which precipitate these accidents. Several patterns emerged from the data. One involved the use of a variety of design and environmentally induced hazards, specifically temporary changes in a stairway due to transient housekeeping or maintenance procedures, or different attributes of a given stairway which made it unusual to a person who more frequently used another stairway. When the performance of a job required that attention not be given entirely to negotiating the stairway, the probability that an accident would occur increased greatly. This is an already well documented problem of task overload in accident producing situations. Using a matched pair of stair users who did and did not have accidents as recorded on videotapes, an attempt was made to identify precipitating environmental and behavioral factors, including type of clothing worn, use of handrail, carrying of items, or speed of movement. Risers in excess of 6 to 7 inches in effective height, treads of less than 10 to 11 inches in effective depth, and tile or linoleum tread materials each contributed to accidents occurring. Concrete or stone treads, and the presence of visual distractions to the side of the user's path of travel were associated with lower incidence rates.