A deep sea diver from Harpenden died in what has been described as a "tragic accident" when air caught in his lungs expanded, causing them to burst.
Toby Wilson, of Aysgarth Close, passed away on October 4, 2012, during a family holiday to the Philippines.
The 37-year-old, who had completed more than 60 dives previously, died when the air in his lungs expanded damaging the fragile tissue.
This condition, which is officially called pulmonary barotraumas, was caused by the change in pressure from ascending towards the surface.
Mr Wilson’s mother Lindsey said: "It came as a huge shock.
"We weren’t expecting it and we miss him dreadfully.
"He was doing what he wanted to do.
"He had been diving for many years. Every year he would go to different places."
Mr Wilson had been on the second of six dives he had planned for the two week holiday with his father, Ian, and step-mother, Lorraine, when he died.
He was part of a group of divers that travelled to a shipwreck about 14 miles away from the resort.
While they were underwater one of the professional divers noticed that Mr Wilson had used more of his oxygen than he should have.
He signalled to him to check how he was feeling, to which Mr Wilson replied he was fine.
However the other divers were concerned so one took him by the arm and the pair made their way to the service.
On the way up Mr Wilson gestured that he was in trouble by pointing towards his heart.
When he reached the surface Mr Wilson was sick and then lost consciousness.
He was given oxygen and CPR before being rushed to Coron District Hospital where he was pronounced dead.
At an inquest today (Wednesday) at Hertfordshire’s Coroners Court in Hatfield, coroner Edward Thomas ruled that the death was accidental.
He said: "He was an experienced diver.
"He died of a tragic accident.
"It is an awful tragedy."