Building construction activities and accidents on construction sites are significantly rated high in Nigeria. To reduce this problem, various building construction sites in Minna metropolis were studied and the aim was to determine the extent in which the health of workers are being affected by the construction activities by taking into considerations, the sources of responsible hazards, in order to generate guidelines to reduce hazards in construction sites in Nigeria. 10 different areas in Minna metropolis were used for this research. In each of these areas, data were collected from two building construction sites. The types of buildings that were studied are residential, commercial and institutional buildings. Primary data were obtained through interviews and structured checklist. In each of the building construction site, five workers were interviewed. Secondary data were obtained from the reviews of relevant academic materials to this research. Tables and content analysis technique were used to present the data. Among the findings are: the majority of workers have no protective clothing and the frequency of this loop hole is significantly rated very high in all the building construction sites; some workers do not have boots to protect their feet in all the building construction sites that were studied; Among the recommended guidelines are: it must be ensured by the building engineers or the project managers that all the workers should have protective clothing, in order to minimise injuries during the construction activities on the building construction sites; it must also be ensured by the building engineers or the project managers that all the workers should have boots to protect their feet, in order to minimise injuries during the construction activities on the building construction sites.