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Most pallets use treated lumber; you won't want to plant food in one. Wood pallets used to transport food can possibly harbor pathogens such as E. coli and Listeria. However, close contact with pallet wood or inhalation of dusts from sanding or sawing can be a source of exposure to pesticide and fungicide chemicals. It is likely that the January, 2010 recall of Johnson and Johnson Tylenol and other drugs were due to their being stored on wooden pallets that had been treated with the fungicide/pesticide 2,4,6-tribromophenol. This chemical can be degraded by molds to produce tribromoanisole whose strong, musty odor caused consumers to complain. There is no acute or chronic health data on 2,4,6-tribromoanisole, but it is believed that the contaminated drugs caused nausea and other health effects in some people. Just a thought.