The theoretical base of the research of occupational injuries is the idea of
the process as Markov chain of random variables. However the exact proof of
this position was not carried out whereas the experimental passing of the
hypothesis is connected always with the determined confidence limits and
consequently it gives the space for alternative assumptions. In this research
some databases of occupational injuries had been studied using spectral
analysis techniques and the presentation of the occupational injuries as the
temporal sequence of the cases ("telegraph wave" process type).