Aroclor and Other PCB Mixtures
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With few exceptions, PCBs were manufactured as a mixture of various PCB congeners, through progressive chlorination of batches of biphenyl until a certain target percentage of chlorine by weight was achieved. Commercial mixtures with higher percentages of chlorine contained higher proportions of the more heavily chlorinated congeners, but all congeners could be expected to be present at some level in all mixtures. While PCBs were manufactured and sold under many names, the most common was the Aroclor series. For information on the percent weight of PCB congeners present in some common Aroclors, see Plots of Aroclor Composition (PDF) (7 pp, 82K).
Aroclor is a PCB mixture produced from approximately 1930 to 1979. It is one of the most commonly known trade names for PCB mixtures. There are many types of Aroclors and each has a distinguishing suffix
number that indicates the degree of chlorination. The numbering standard for the different Aroclors is as follows: The first two digits generally refer to the number of carbon atoms in the phenyl rings (for PCBs this is 12), the second two numbers indicate the percentage of chlorine by mass in the mixture. For example, the name Aroclor 1254 means that the mixture contains approximately 54% chlorine by weight. See the Table of Aroclors (PDF) (1 pg, 19K) for a list of common Aroclors.
PCBs were manufactured and sold under many different names. The names in the following table have been used to refer to PCBs or to products containing PCBs. Please note:
- Some of these names may be used for substances or mixtures not containing PCBs.
- Many of these names were used with distinguishing suffixes, indicating degree of chlorination, type of formulation, or other properties (e.g., Aroclor 1254; Clophen A60).
- Some of these names may be misspellings of the correct
names, but are included here for completeness.
PCB Trade Names