Braun on a four-way pallet in 1945, and a patent from Norman Cahners (a U.S. Navy supply officer) shows a disposable pallet in 1949. The principle of a modern four-way pallet is described by Darling Graeme in 1949. Hazards Fire hazards Both wood and plastic pallets are possible fire hazards. The National Fire Protection Association requires that both types "shall be stored outside or in a detached structure" unless protected by fire sprinklers. Contamination risks Items made from pallet wood are likely to be durable and demonstrate good weather resistance due to these treatments. 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 was 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 2,4,6-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. Wood pallets used to transport food can possibly harbor pathogens such as E. coli and Listeria. A press release by the National Consumers League announced the testing of 70 wood pallets and 70 plastic pallets that have been loaded with perishable products and shipped to an end user was shipped overnight to an independent microbiology lab for testing. The results came back with 10 percent of the wood pallets (7 pallets) positive for E. coli and 1.4 percent (1 pallet) positive on the plastic pallets. Air cargo pallets An air cargo pallet is a detachable and interchangeable airworthy floor panel. It can be loaded and unloaded on aircraft to transport air cargo Most less than thick, for a Cargo aircraft. Many civilian types have evolved over 6 decades from the thicker military '463L Master Pallet'. When combined with a cargo net, an air cargo pallet becomes an aircraft 'Unit Load Device' and must be inspected for integrity before use in an aircraft. It is handled on dedicated roller or ball-mat ground equipment and vehicles (fork-lifting is prohibited especially when the pallet is loaded). Pallet boxes Pallet boxes are pallets with four pallet walls on top and possibly a lid. Unlike pallets, pallet boxes