An electrical ballast is a device intended to limit the amount of current in an electric circuit. Ballasts vary greatly in complexity. They can be as simple as a series resistor as commonly used with small neon lamps or light-emitting diodes (LEDs). A more complex type is one that uses reactance. Losses in the ballast due to its resistance and losses in its magnetic core may be significant, on the order of 5 to 25% of the lamp input wattage. Practical lighting design calculations must allow for ballast loss in estimating the running cost of a lighting installation. Prior to 1980 in the United States, PCB-based oils were used as an insulating oil in many ballasts to provide cooling and electrical isolation. Older buildings (including schools and commercial operations) will often have PCB ballasts in their fluorescent lights even today because the ballast will work a longer than the bulb. he U.S. Environmental Protection Agency (EPA) today released guidance recommending that schools take steps to reduce potential exposures to PCBs from older fluorescent lighting fixtures. The guidance, part of EPAâ€™s ongoing efforts to address potential PCB exposures in schools, is based on evidence that the older ballasts contain PCBs that can leak when the ballasts fail, leading to elevated levels of PCBs in the air of schools that should not represent an immediate threat but could pose health concerns if they persist over time.
"As we continue to learn more about the potential risks of PCBs in older buildings, EPA will work closely with schools and local officials to ensure the safety of students and teachers," said EPA Assistant Administrator for Chemical Safety and Pollution Prevention Steve Owens. "This guidance on safely addressing the risks from PCB-containing light fixtures is part of EPAâ€™s ongoing efforts to protect the health of our children and provide them with safe, healthy learning environments."
Until the late 1970s, PCBs were commonly used as insulators in electrical equipment because they have a high tolerance for heat, do not easily burn, and are non-explosive. EPA banned the processing and distribution in commerce of PCBs in 1979 pursuant to the Toxic Substances Control Act due to their toxic effects. However, uses of older PCB-containing ballasts were allowed to continue, provided that the ballasts had not failed and the PCBs were not leaking.
EPA believes many schools built in the U.S. before 1979 have light ballasts containing PCBs. A recent pilot study of three schools in New York City found that many light ballasts in the schools contained PCBs and had also failed, causing the PCBs to leak and contributing to increased levels in the air that school children breathe. EPA regional offices have also worked with school officials to address leaking PCBs in light ballasts in schools in Oregon, North Dakota, and Massachusetts.
PCB ballasts are effectively invisible and tend to be hidden in the light fixture. Just a visual inspection is not effective unless one knows the various brand names that may contain PCBs.
Given their widespread use before they were banned, if a school was built before 1979 or has not had a complete lighting retrofit since 1979, the fluorescent light ballasts probably contain PCBs. Although intact, functioning ballasts do not pose a health threat, these lighting ballasts will all fail in time. For that reason, EPA recommends older PCB-containing lighting ballasts should be removed, whether as part of a previously scheduled lighting retrofit program or a stand-alone project.
Schools that have older ballasts should examine them to see if they have failed or if PCB leaks are present. If a light ballast is leaking PCBs, federal law requires the immediate removal and disposal of the PCB-containing ballasts and disposal of any PCB-contaminated materials at an EPA approved facility.
Information on the handling and disposing of PCB-containing light ballasts: http://www.epa.gov/epawaste/hazard/tsd/pcbs/pubs/waste.htm
For further information: http://yosemite.epa.gov/opa/admpress.nsf/0/6C03FDEC1E63274C8525780800693D7D