Health and Environmental Care Procedures for Mineral Insulating Oil
Health issues
Users should obtain an MSDS for each dielectric fluid in use. Where instructions differ from recommendations made here, the instructions of the manufacturer are to be followed. Although no special risk is involved in the normal handling of insulating fluids addressed in this guide, attention should be focused on the general need for personal hygiene or the practice of washing skin and clothing that may have come in contact with insulating oil. Personnel should avoid contact of the fluid with their eyes. When dielectric liquids have to be disposed of, certain precautions are necessary to comply with local, state, and federal requirements in the United States. These oils are generally classified as special, regulated, or hazardous waste depending on the individual state. The following procedures are not intended to supersede local, state, or federal regulations. Unless a PCB analysis has been performed, it is prudent to assume that the batch of oil contains PCBs and to act accordingly. The absence of PCBs in a volume of oil in or from a piece of equipment can be established only by analysis of that oil.
Leaks and spills
During equipment inspection or servicing, routine checks should be made of the equipment and surroundings for leaks. Areas to check and repair should include valves, bushings, gauges, tap changers, welds, sample ports, manhole covers, pipefittings, and pressure relief valves. The user is referred to IEEE Std 980.
New transformer oil as received from a refiner is very unlikely to contain PCBs. However, many older transformers and other pieces of electrical equipment in service are filled with mineral insulating oil that contains PCBs. Since 1977, various federal, state, and local environmental regulations have governed the handling and processing of mineral oils containing PCBs. Although these regulations can add substantially to the complexity of spill cleanup and disposal of oils, they should not be disregarded.
Minor spills
Minor spills, such as those occurring in the manufacture or repair of equipment, can be cleaned using absorbent rags or other materials.
Spills on soil
Soil acts as an absorbent and should not be allowed to become saturated with mineral insulating oil. Users should consult the applicable local, state, and federal guidelines (see Title 40 CFR, Part 112) in the United States for spills of mineral oil onto soil and the remedies available. Depending on state and local regulations, spills to soil may have to be reported to one or more regulatory agencies.
Spills on water
Because mineral insulating oils float on water, a spill can be contained by using floating booms or dikes. Section 311 of the Federal Water Pollution Control Act as amended, 33 U.S.C. 1251 et seq, also known as the Clean Water Act as found in Title 40 CFR, Part 110, imposes reporting requirements for petroleum oils that are spilled into navigable water ways. The requirement to report is triggered by discharges of oil that cause a film or sheen upon or discoloration of the surface of the water or adjoining shorelines or cause a sludge or emulsion to be deposited beneath the surface of the water or upon adjoining shorelines. The U. S. Coast Guard must be notified as well as the National Response Center.
Once the mineral oil has been concentrated, it can be removed from the surface of the water by systems that are normally used for petroleum spills. These systems include pumps, skimmers, physical absorbents, and fibers that are fabricated into floating ropes.
NOTE - If spilled mineral insulating oils are known or assumed to contain any concentration of PCBs, they must be treated as a PCB containing liquid. Also refer to the Spill Policy Guide of the Environmental Protection Agency (see Title 40 CFR, Parts 761.120 and 761.61).
