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 main housing with an oxygen-generating chemical core, a spring-loaded initiation mechanism, and a breathing apparatus (e.g., mouthpiece or mask/tubing). The device is intended to be used by healthcare professionals and laypersons. This is a single-use device.