A portable, non-electric device designed to produce medical grade oxygen, from activated chemicals, to administer to patients in first aid or emergency situations (e.g., cardiac emergencies, asthma/COPD exacerbations, shock/ trauma in the field). It consists of a reusable housing with an activation button, a single-use breathing apparatus (e.g., mask/tubing), and a replaceable single-use oxygen-generating chemical cartridge. The device is intended to be used by healthcare professionals and laypersons. This is a reusable device upon replacement of single-use components.