Hello go on google to pallet identification it shows all the symbols and codes thr one to worry about most is any that have M,B on then as these were treated with Methyl Bromide up to 1993 when they were banned but some can still be in circulations food carrying pallets,if you have blue ones make sure that they are legally sourced as a company owns them and they are chargeable £5.00 ,if blue ones are broken or damaged they can be used, there are now reddish purple ones these are CHEC marked I havent found out yet if these are chargeable but they are returnable jezza