HANDLING AND STOWAGE OF HAZARD- OUS MATERIALS. —A hazardous material is any substance or mixture of substances that could result in the injury or death of a person. These substances are divided into toxic, irritating, flammable, pressurized, or sensitizing agents. The hazardous material could also result in damage to equipment or personnel through corrosion, oxidation, pressurization, or heat-generation. As you were climbing the advancement ladder, your major concern about safety was your own well-being. As a senior petty officer, you should be concerned not only about your own safety but also the safety of others. You should make sure all  personnel  observe  the  following  general precautions when handling and stowing hazardous materials: • • • • • • • • • • • Keep stowage compartments clean and dry. Provide adequate ventilation in the storage area. Provide separate storage areas for materials that would become dangerous if mixed or combined. Avoid stowing materials in direct sunlight if the sun rays could cause a harmful or an unstable effect to the material. DO NOT allow unauthorized personnel in the stowage area. Make sure the precautionary label remains intact after each use or when transferring the material to another container. Inventory the containers quarterly. Inspect  the  containers  for  tightness  of cover seal, corrosion, leakage, improper or inadequate labeling, and shelf life expiration date. NEVER allow open flames in the stowage or handling area. Monitor the stowage area for oxygen depletion or toxic gas buildup (this check must be accomplished by a gas-free engineer). ALWAYS use electrical equipment that is authorized for use in an explosive atmosphere. SECURITY. —Designated departmental supply custodians are responsible for safeguarding the material under their control; therefore, security is always an important consideration. Storerooms must be kept locked when not in use. The number of people having direct access to a storeroom should be kept to a minimum; otherwise, material could disappear and the custodian would have no record of its issuance. Control and responsibility should be clear-cut; that is, clear-cut decisions on the  following  questions  should  be  made  and enforced within the responsible department: 1. 2. 3. 4. Who is primarily responsible for keeping the keys to each storeroom? To whom are the keys given when the custodian goes ashore? Where may personnel on watch find the keys (or duplicate keys) if a storeroom has to be entered in case of emergency? Who else, if anyone, should have direct access to the storeroom? PHYSICAL ARRANGEMENT. —The physical arrangement  of  storerooms  depends  on  the construction of the portions of the ship in which the storerooms are located. Each stowage area presents particular problems and should be considered separately to ensure that the available stowage space is used to full capacity. Material should be segregated into arrange- ments  best  suited  for  purposes  of  issue  and inventory, with special attention to placement of fast-moving items for convenience of issue. When repair parts are stowed in boxes, consideration should be given to the department’s planned maintenance program. In most cases, material should not be stowed in stock number sequence, since  national  stock  numbers  assigned  are not necessarily related to item characteristics. For maximum stowage life, stowage should be planned so that the oldest material is issued first. Small  ships  do  not  usually  have  suitable stowage space. Material has to be stowed in small spaces that are irregular in shape and size. Orderliness may have to be sacrificed to put materials in the spaces that best fit them. For example, bulky items may have to be stowed in inconvenient, out-of-the-way spaces because the size of hatches and passageways prevents their stowage with related items. However, do not overload the bins at the expense of safety and accessibility. 4-16