OSHA regulation 1910.151(b) states that, "In the absence of an infirmary, clinic, or hospital in near proximity to the workplace which is used for the treatment of all injured employees, a person or persons shall be adequately trained to render first aid. Adequate first aid supplies shall be readily available." OSHA tends to define "near proximity" as a 3-4 minute response time from time of injury to time of administering first aid, which means that a hospital or clinic would need to be a 1 minute drive away from your workplace (factoring in time to get to you car and drive to the hospital). As this proximity is unlikely for the majority of workplaces, it is necessary to have at least one person in the workplace (for each shift) that is trained in First Aid.
Do you know how easy and affordable it is to get First Aid, CPR, and AED certified? You can even do it online. In fact, you can even get First Aid and CRP certified for free. It's so easy to find a location or train online that there's no excuse for being non-compliant with this regulation.