Data is available for OSHA compliance but are the regulations themselves available through web services? Is there an ontology for OSHA regulations? If not, would the DOL be interested in developing one (possible collaboration)?
Referring to the text at OSHA, these have not been coded into an ontology by OSHA. There are various subsets that have been coded into ontological forms sufficient for logic processing by research projects, e.g., Ontology-Based Representation and Reasoning Framework for Supporting Job Hazard Analysis, but they are not sanctioned nor maintained by OSHA. I believe that you might find some of the groups willing to release, but, again, I seriously doubt that much effort is being invested in maintaining the vast majority of even these subsets once the study is complete due to the lack of commercialization of any of the research outputs.