Also, how much space will be required to store 26 Pallets of bottled water?
The vast majority of the pallets I have seen don't seem to be pressure-treated wood (occasionally I have seen them repaired with it though). Pallets get collected and re-used over over so they could have been exposed to almost anything at some point. The methyl bromide (and possibly other substances) are probably there only as trace contaminants from treating fruit, vegetables, grain, etc to avoid fungus and vermin infestation. Sometimes they get splattered with spilled chemicals, oils, tar, paint, fertilizers and other materials when somebody skewers drums, bags and other containers with the forklift. If there is any significant contamination, you can usually see stains, deposits on, or oily matter sogged into the wood. Often there will be a weird odor as well. I try to use the newest/cleanest looking ones. By the way, be careful if you are running boards from pallets through a table saw or planer, they often re-use boards recovered from damaged pallets to fix other ones and they often still have the head ends of the old nails cut off in the wood they don't show up very well! They can trash your blades and fly out as well.
Excellent answer flying dragon.
