The city Medical Examiner’s Office has determined that the deaths of five men in an underground Waikele storage facility last Friday were caused by an accidental explosion of fireworks in a confined area.

Other federal and city agencies are continuing investigations into what caused  the explosion.

The Medical Examiner’s Office identified four of the men: Robert Kevin Freeman, 24, of Aiea; Bryan Cabalce, 25, of Wahiawa; Neil Sprankle, 24, of Mililani; and Justin Kelii, 29, of Kaneohe. The fifth man has been identified by family members as Robert Leahey, 50.

The bodies of Freeman and Leahey were recovered soon after the accident about 9 a.m. Friday Examiners said the cause of death for both men was thermal burns and the toxic effects of carbon monoxide inhalation due to an explosion in a confined space.

Cabalce, who was taken to Straub Clinic and Hospital in critical condition, died at 5:50 p.m. Friday of thermal burns due to the explosion.

The bodies of Sprankle and Kelii were removed from the cave Saturday. Examiners said the two men died of asphyxia due to the toxic effects of carbon monoxide inhalation caused by the explosion.

Police and fire crews said the unstable environment of the cave, which continued to have explosions through much of Friday, prevented them from going into the cave to retrieve Spankle and Kelii until the following day.

Police and fire officials say the five men, along with a sixth man who was injured slightly but refused treatment, were employees of Donaldson Enterprises, a company contracted to store and dispose of confiscated aerial fireworks.