Is there anyone who can explain to me how occupational health workers works in Us?

I am working at an Oil Refinery as an Occupational Nurse. We have approximately 236 employees. My primary responsibility is worker safety. I respond to any incidents, perform First Aid as needed. I administer injections, perform audiometric testing, pulmonary function testing, blood draws, vision screenings, whatever is necessary. I work under the direction of a physician who is not on site but is our Medical Director. I work along side of the plant Fire Brigade and we also have EMT's, and First Responders. It is a very enjoyable position and a first for me and the plant as well. They have never had a nurse on site so it has been quite an experience!!!