Risk assessment of workplace mobbing Magdalena Warszawska-Makuch, p. 8-11 Reducing the intensity of teachers voice and reduce background noise level in the classroom after the acoustic treatment Witold Mikulski, Izabela Jakubowska, p. 10-12 Interference film against harmful infrared radiation in hot workplaces Grzegorz Gralewicz, Grzegorz Owczarek, Jerzy Kubrak, p. 12-15 Safety management in non-Seveso establishments in control of major accidents - necessary management procedures (1) Jerzy S. Michalik, Agnieszka Gajek, p. 16-19 Social cost of occupational accidents Jan Rzepecki, p. 20-23 Lab research on the influence of ultrasonic noise on human cognitive skills and psychomotor capability Bożena Smagowska, Witold Mikulski, p. 24-26 Risk assessment of workplace mobbing Magdalena Warszawska-Makuch This paper presents effects and potential causes of workplace mobbing, especially in the case of organizational factors. It also presents the tools to assessment risk of workplace harassment which were developed until now, including Polish Questionnaire (ORM) which was developed in CIOP-PIB. It also discusses the way of development of the tool, its structure, psychometric characteristics and practical use. Reducing the intensity of teachers voice and reduce background noise level in the classroom after the acoustic treatment Witold Mikulski, Izabela Jakubowska The acoustic properties of classrooms for verbal communication are characterized by reverberation time and the speech transmission index. From the teachers’ point of view, it is also important what voice intensity is necessary to ensure an acceptable level of communication. In rooms with shorter reverberation time, background noise is reduced, which enables a reduction in the teacher''s voice intensity, without a decrease in the quality of verbal communication. This is due to the fact that speakers unconsciously and without thinking adjust the volume of their voice, so that it is several decibels higher than the level of background noise (the so-called Lombard’s effect). This article presents the results of research on determining the density distribution of sound pressure level in the classroom, from which the level of the teacher’s voice and background noise are determined. Interference film against harmful infrared radiation in hot workplaces Grzegorz Gralewicz, Grzegorz Owczarek, Jerzy Kubrak This article presents basic information on blocking harmful infrared radiation with optical filters with thin-film coatings. Interference structures for efficient blocking of harmful radiation were calculated and analyzed. The construction of new interference optical filters against infrared radiation was compared with currently available filters. Safety management in non-Seveso establishments in control of major accidents - necessary management procedures (1) Jerzy S. Michalik, Agnieszka Gajek As a result of research carried out in 2008-2010 it has been found that non-Seveso establishments pose a relatively greater risk of a major accident, than lower- and upper-tier establishments. As demonstrated by numerous inspections of the State Labour Inspectorate (PIP), the state of safety management in the context of control of major accidents in non-Seveso establishments is quite insufficient. Taking into account those circumstances, proposals were developed for elements and procedures of safety management systems concerning prevention of major accidents and limitation of their effects in non-Seveso establishments; they take the form of recommendations presented in this publication. Social cost of occupational accidents Jan Rzepecki This article presents a method of calculating the social cost of occupational accidents embracing primary factors of the social cost of occupational accidents. It also presents a proposal for classifying accidents and registering data on the cost of accidents borne by employers. Moreover, the article discusses the results of a pilot check of the method, on the basis of five companies in which a survey was conducted. Lab research on the influence of ultrasonic noise on human cognitive skills and psychomotor capability Bożena Smagowska, Witold Mikulski This paper presents the method and results of laboratory tests conducted to determine the influence of ultrasonic noise on cognitive skills and the psychomotor capability of the human body. The method was based on the change in mental capacity of subjects exposed to ultrasonic noise in such function as reflexes, observation skills, attention and work output, subjective estimation of mood and tiredness of the subjects. Those functions were assessed with indicators from psychological tests and the basis of questionnaires. A preliminary criterion of annoyance of ultrasonic noise was developed (in the third band 31.5 kHz).