Almost every business is required to have an emergency action plan (EAP).
If fire extinguishers are required or provided in your workplace, and if anyone will be evacuating during a fire or other emergency, then OSHA's 29 CFR 1910.157 requires you to have an EAP.
The only exemption to this is if you have an in-house fire brigade in which every employee is trained and equipped to fight fires, and consequently, no one evacuates.
In most circumstances, immediate evacuation is the best policy, especially if professional firefighting services are available to respond quickly. There may be situations where employee firefighting is warranted to give other workers time to escape, or to prevent danger to others by spread of a fire. In this case, you as the employer are still required to have an EAP.
To help you decide whether to have employees evacuate or fight fires, see the Fight or Flee? section of this eTool.
Still unsure about whether you are required to have an EAP??? Use OSHA's Expert System to help you determine whether you are required to have an EAP.