No, offering any Emergency Services which connect users to emergency services personnel or public safety answering points, such as 911 or E911 services, violate Twilio's Acceptable Use Policy and is not allowed.
It is acceptable to use Twilio to send notifications that do not directly impact life safety. For example, early warning alerts, safety advisories, event cancellations, etc. are allowed. We always recommend building in redundancy for important applications and using Twilio's notifications in conjunction with other public warning systems like sirens, radio and TV broadcasts if applicable.