The EMCOM US talkgroup is dedicated to "personal" emergency use.
There is some debate surrounding its use, however, as this is a WIKI, I will share my thoughts based on how it works within the BrandMeister network. I will simply summarize the talkgroup as for personal emergency alerting or in other words personal MAYDAYS.
This isn’t to say it couldn’t be used in support of a larger scale event, say in the case of an amateur using this if they need to declare a personal emergency, say they become trapped, or injured during an event, and require help.
There are two options for using this talkgroup, and funny enough, they can be used together:
From the website "OPERATING YOUR HAM RADIO IN AN EMERGENCY" (https://www.dummies.com/programming/electronics/operating-your-ham-radio-in-an-emergency/)
Before an emergency occurs, be sure you know how to make a distress call on a frequency where hams are likely to be listening, such as a marine service net or a wide-coverage repeater frequency. Store at least one of these frequencies in your radio’s memories, if possible. Anyone, licensed or not, can use your radio equipment in an emergency to call for help on any frequency. You won’t have time to be looking at net directories in an emergency. Do the following things when you make a distress call. If you need immediate emergency assistance, the appropriate voice signal is MAYDAY and the appropriate Morse code signal is SOS (yes, just like in the movies). Maydays sound something like: “MAYDAY, MAYDAY, MAYDAY, this is [your call sign]” followed by:
Repeat your distress signal and your call sign for several minutes or until you get an answer. Even if you don’t hear an answer, others may hear you. Try different frequencies if you do not get an answer. If you do decide to change frequencies, announce to what frequency you are moving so that anyone hearing you can follow. If you hear a distress signal on the air: Immediately find something to record information. Note the time and frequency of the call. To help the authorities render assistance as quickly as possible, note the following information:
Respond to the call. Say “[Give the station’s call sign], this is [your call sign]. I hear your distress call. What is your situation?” Using Morse code, you send “[station’s call sign] DE [your call] RRR WAT UR INFO?” or something similar. Let the station in distress know who you are and that you hear them. After you acquire the information, ask the station in distress to remain on frequency. Call the appropriate public agency or public emergency number, such as 911. Follow the dispatcher’s instructions to the letter. The dispatcher may ask you to act as a relay to the station in distress. As soon as possible, report back to the station in distress. Tell them who you contacted and any information you have been asked to relay. Stay on frequency as long as the station in distress or the authorities need your assistance.