Great demands for oil and oil derivatives, as well as the specificity of oil transportation due to properties that can endanger the ship, the environment, health and safety of the crew have caused many determinants for safety management and safe handling of the ship. The ISM Code provides an international standard for the safe operation and handling of a ship, and the prevention of pollution. It also requires the development of SMS, a safety management system, which provides specific guidance for each ship in carrying out various operations, as well as regulations for risk assessment, ship procedures and a work permit system. A very important publication, ISGOTT (International Safety Guide for Oil Tankers and Terminals) contains a series of guidelines for performing dangerous operations that can have negative impact on ship, crew or environment. Through this paper, we touched on guidelines and procedures when entering enclosed spaces, and the conditions that need to be met in order to enter with as little risk as possible. Also, the procedures for hot work, as well as hot work outside designated area and inside hazardous or toxic areas are explained. The focus is on the dangers arising from the flammability and toxicity of petroleum, and the procedures that need, to be followed in order to bring the risk of operations within acceptable limits.