 An ambulance with only EMTs is considered a Basic Life Support (BLS) unit, an ambulance utilizing AEMTs is dubbed an Intermediate Life Support (ILS), or limited Advanced Life Support (LALS) unit, and an ambulance with Paramedics is dubbed an Advanced Life Support (ALS) unit.Many states allow ambulance crews to contain a mix of crews levels (e.g.an EMT and a Paramedic or an AEMT and a Paramedic) to staff ambulances and operate at the level of the highest trained provider.