Though Delevingne was involved with many aspects of the Home Office, he was particularly concerned with occupational health and safety, with special focus on regulations for factories and coalmines. He was instrumental in the passage of the Police, Factories, etc. (Miscellaneous Provisions) Act of 1916, which required workplaces to provide first aid, washrooms, drinking water and other amenities. He did a considerable amount of work on the Coal Mines Act, 1911, which required all mine owners to establish rescue stations, provide teams of trained rescuers, and to keep and maintain rescue apparatus on site.