This is the CodeSystem that contains all the codes in Occupational Data for Health (ODH) (http://terminology.hl7.org/CodeSystem/PHOccupationalDataForHealthODH) and Occupational Data for Health (ODH) (http://terminology.hl7.org/CodeSystem/PHOccupationalDataForHealthODH). E.g. what you have to deal with if you get resources containing codes in either of them