We present the case of an adult white man found dead in a psychiatric institution with fine white powder (monoammonium phosphate) deposited over the entire face after he insufflated the contents of a dry chemical fire extinguisher. Fine white powder was present within the mouth and sinuses and lined the upper airways. On opening the thoracic cavity, approximately 500 g of fine white powder was present within the right thoracic cavity. The esophagus was ruptured. Traumatic emphysema of the posterior sternum wall was present (pneumomediastinum). The ethmoid bones were fractured by the barotrauma. On polarization of the lung tissue, birefringent material was noted deposited along the bronchovascular sheaths and in a subpleural distribution. Death was probably due to a combination of barotrauma and asphyxia.This case study provides strong evidence in support of the etiology and pathophysiology of the Macklin effect. It also provides for the first visual evidence of the phenomenon.