FATAL INJURIES: Royal Australian Air Force Sergeant Michael Dunn died as a result of injuries he sustained during an explosion at Rockhampton Airport.

The Royal Australian Air Force is mourning the loss of an airman, who was critically injured in a portaloo explosion during military exercises in July.

RAAF chief Air Marshal Geoff Brown said Air Force Sergeant Michael Dunn died in hospital this morning from injuries sustained during an explosion at Rockhampton Airport on July 25.

Air Marshal Brown expressed his deepest sympathies to Sergeant Dunn's family.

Sergeant Dunn was highly respected and well-liked by his colleagues. Those who visited Mick since the accident were all affected by the courage and determination that he showed during his treatment and are extremely saddened by his passing,â€ he said in a written statement.

Our thoughts are with the family, friends and colleagues of Sergeant Dunn."

Sergeant Dunn's family has requested privacy, but shortly after the explosion they released a statement through the Australian Defence Force, in which they were "not giving up hope of a good recovery".

"We are very grateful for all the messages of support from family, friends and members of the community, which are helping us work through this period of uncertainty," they said at the time.

"We're particularly grateful for the efforts of the dedicated staff in the Burns Unit who are doing their very best for Mick."

Air Marshal Brown said Sergeant Dunn had served 27 years in the RAAF.

"Most recently, he was serving at RAAF Base Tindal where he and his family were long-standing members of the Katherine community, "he said.

"The safety of all Defence personnel is the highest priority for the Australian Defence Force. A full and thorough investigation into the incident at Rockhampton Airport is continuing, and further details may become available once the investigation is complete."

Sergeant Dunn was using the portable toilet at about 9.30am after possibly being exposed to a fuel spill, an ADF spokeswoman said. She said the cause of the ignition was still being investigated.

Sergeant Dunn suffered third-degree burns to his head, face, arms, chest and airways and was taken by ambulance to Rockhampton Hospital in a serious condition and was later transported to the Royal Brisbane and Women's Hospital.

Sergeant Dunn had been participating in the Australia-United States joint military exercise Talisman Sabre 2011, which was underway at the airport.