MIL-STD-464D is the current revision of the United States military standard for electromagnetic environmental effects requirements at system level, superseding the previous edition. It retains the structure of its predecessor, in which the requirement is placed on the platform rather than on the equipment, and in which the verification is achieved through a combination of analysis, modelling and test agreed with the procuring authority. Programmes applying it must identify the electromagnetic environments the platform will meet, the safety margins to be preserved between emissions and susceptibilities, the hazards to personnel, fuel and ordnance, and the effects of lightning, nuclear electromagnetic pulse and high intensity radiated fields, and must then demonstrate compliance through a verification plan whose content, evidence and acceptance criteria are negotiated rather than prescribed in detail. For a supplier the practical consequence is that the applicable revision and the agreed verification approach should be confirmed at the beginning of a programme.