The source of TBA-contaminated drug products appears to have been 2,4,6-tribromophenol (TBP), a chemical used as a wood preservative. Certain fungi are able to survive in TBP-treated wood by converting TBP to its anisole analog, TBA.1 In the contamination incident, an investigation found that TBP-treated wood was used to manufacture pallets that were then used to ship and store drug packaging material. Currently, the use of halogenated phenolic compounds to preserve wood appears to be very rare as this practice is either discouraged or prohibited in many regions of the world, including the United States. However, TBP treatment of wood continues in some regions that supply wood to the United States and other ries.
1Trichlorophenol (TCP) is another example of a compound that can be converted to a halogenated anisole compound.
