ISPM-15 is the international standard for heat treating / sterilising wooden pallets. All whole-wood pallets should have the ISPM-15 stamp visible. I had read, before organising my shipments, that non-compliant pallets are not allowed to be exported from the USA. So I am surprised that the wood got through, however I have never tested the 'theory'. Other forms of processed wood (ply/fibreboard/wood composites) are acceptable in an untreated state. If lucky and you have no other options, you may find IPSM-15 stamped pallets on eBay local to the seller. Otherwise some importers will help you source them. The importer I use offered to swap my pallets over if needed but I always managed to get my stuff packed onto an ISPM-15 pallet.