Those experiencing an emergency in L.A. County can now text 911 if calling isn’t an option.

Officials launched the Text-to-911 program as a way to help Angelenos who might be situation where it is too dangerous to speak on the phone, such as domestic violence case or active shooter emergency. The text messaging service will also give hearing and speech-impaired residents the ability to report emergencies more easily.

Some important things to keep in mind: