PCBs are produced by the chlorination of "biphenyl." One to ten hydrogen atoms of biphenyl can be replaced with chlorine atoms. Given all the possible arrangements of chlorine atoms, there are 209 compounds that are classed as chlorinated biphenyls.
Commercial mixtures of PCBs were manufactured in the U.S. by the Monsanto Chemical Company and sold under the trade name of Aroclor. Aroclors 1260, 1254, and 1242 were most frequently used in electrical euipment. These Aroclor designations refer to the PCB mixture. Aroclor 1260 is 60% chlorine by weight, 1254 is 54% chlorine by weight and so on.
As insulating fluids in electrical equipment, Aroclors were seldom used in pure form, but were frequently mixed with fluids such as trichlorobenzene or tetrachlorobenzene. These Aroclor-fluid mixtures are generically called Askarels. Brand names for Askarels are shown below.
|The EPA has classified electrical equipment and insulating
fluids according to the level of PCB contamination. The EPA’s
classifications of equipment and fluids are shown in the table below.
Regulations set forth by the EPA have made it cost effective to determine
the level of PCB contamination prior to disposal of eqipment or fluids.
Delays caused by slow laboratory service may leave a repair shop idle while
wating for PCB test results. Inaccurate determination can lead to an
unnecessary increase in disposal costs. Prompt, reliable results are
mandatory for PCB analysis.|
Manufacturers’ names used for PCBs