FOREWORD: The safeguarding of human life against accidental injury or death has become a vital factor in the conduct and development of modern industry. In no part of any industry has this been more emphasized than in the producing and refining of petroleum. Due to the complexity of operations incident to those processes and the revolutionary changes and rapidly expanding and developing nature of the business@ it has become highly desirable to prepare comprehensive manuals in which instructive and descriptive information may be made available for the guidance of the industry's workers. This manual was prepared for the use of executives@ superintendents@ and foremen who are responsible for the issuing of instructions for the guidance of workers engaged in tank cleaning. The manual is so prepared that it may be used as a guide by sub-foremen. It is the object of this manual to present in convenient form information which will promote the safety of workers engaged in the cleaning of petroleum storage tanks. In it are described the common sources of accidents and the usual methods and equipment used in tank-cleaning operations. This information is followed by a short series of recommended safe practices. These recommended practices are based upon the experience of many companies whose representatives have co-operated and assisted in the preparation of the manual. This manual should not be confused with federal@ state or insurance requirements; however@ it is in general accord with the intent and spirit of such regulations. This Manual on Cleaning Petroleum Storage Tanks was prepared by the Committee on Accident Prevention in Refineries and has been approved uy the General Committee@ Division of Refining@ American Petroleum Institute.