There are some emergencies which can't wait five minutes for EMT's to arrive. Severe bleeding is one of these. A person can bleed to death in three to five minutes depending on the severity. Employees need to be available to deal effectively with this and other serious emergencies.
OSHA specifies in 29 CFR 1910 that first aid kits need to be specified by the
consulting physician. Employees should be trained in the appropriate use of the
materials provided. First aid and CPR courses can be offered. You can't expect people
to respond properly to emergencies unless they have an opportunity to practice.