Every day in workplaces, continues events occur that cause death and injury. These accidents usually happen because of lack of exploring the potential hazards and lack of training of employees. Hence, with exploring and evaluating the hazards of workplace and utilizing the suitable procedures, it is possible to prevent from many of these hazardous incidents. Exploring, evaluating and controlling the potential hazards have been the initial stages of scientific safety assurance in every system. Preliminary hazard analyzing is the first effort in analyzing hazards. In this method, usual hazards in sighted job are explored, using the usual hazards table for developing the basis of PHA, the PHA checklist is prepared and at last the PHA table completed and the appropriate suggestions are given. In this paper, we present an implementation of PHA method in one of industries located in city of Tehran, Iran. The proposed study uses 15 explored hazards, where 2 are unacceptable, 9 are undesirable and 4 are acceptable with need of revisal. By eliminating and reducing each hazards risk, some controlling solutions are suggested. The most important of these solutions are utilizing and using the regulations of the welding with electrical archer.