Electric shock accident is one of the main causes of fatal construction accidents. In this study, 101 electric shock accidents are analyzed to mine the potential associations of human errors. The modified Human Factors Analysis and Classification System (HFACS) is used to classify human factors of accident causes. Characteristics and potential causes of the accidents are identified by employing frequency analysis. Chi-square test and Apriori algorithm are utilized to explore the associations among the causes. Some significant association between any of two factors are shared. According to association rules using three criteria: support ( S), confidence ( C) and lift ( L), the two key paths are extracted based on the hierarchy of the HFACS. One is: organizational process loopholes → failed to correct problem → perceptual and decision errors ( S = 0•11, C = 0•423, L = 1•02), and the other is: organizational process loopholes!poor skill level ofworkers!routine violation ( S = 0•149, C = 0•789, L = 1•945). Managerial implications are proposed to prevent or reduce accidents based on interconnections of factors and key paths.

Increased efficiency of production and improved quality have contributed to the development of ultrasonic technological applications, in which low frequency ultrasounds are generated to operate, accelerate as well as to facilitate technological processes. Technological ultrasonic devices (i.e. sources of ultrasonic noise in the work environment, e.g. ultrasonic washers, ultrasonic welding machines) have relatively high power and their nominal frequencies are in the range from 18 kHz to 40 kHz. In Poland, ultrasonic noise (defined as noise containing high audible and low ultrasonic frequencies from 10 kHz to 40 kHz) is included in the list of factors harmful to health in the work environment and therefore the admissible values of ultrasonic noise in the workplaces are established. The admissible values of ultrasonic noise and the new ultrasonic noise measurement method make it possible to perform the assessment of occupational risk related to ultrasonic noise. According to this method, the scope of the measurements includes the determination of the equivalent sound pressure levels in the 1/3 octave bands with the centre frequencies from 10 kHz to 40 kHz. This paper presents the description of both, i.e. the method for ultrasonic noise measurements and the method of the assessment of occupational risk related to ultrasonic noise. The examples of the results of the assessment of occupational risk related to exposure to ultrasonic noise are also discussed.