Twenty senators signed a letter Tuesday to Federal Communications Commission chairman Ajit Pai.
The FCC plans to include quake alerts as part of the system for notifying Americans about emergencies like dangerous weather, fires, and shooters.
Tuesday's letter urges Pai to make sure that any changes account for cellphone network latency - delays in data transmission as the signal jumps between cell towers.
The senators say the success of earthquake alerts relies "on extremely rapid, low-latency alert times."
They write that recent quakes in California and Washington state highlight the urgency of the issue.
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