Can a company safe work practice be developed from a EHS code of practice?

Yes, Partly; as the EHS code of practices can be taken as the legal guidance for the company management system framework and the rest of it depends on the business the company involved in.

PS: Not all the EHS COP covers every business legal compliance or the guidance to work safely, so mostly have to look up for International legislation such as OSHA, Health and Safety Executive - UK, etc.)