No carbon monoxide (CO) alarm was fitted on a fishing boat on which the two crewmen were found dead in their bunks, a marine accident report has said.
Mark Arries, 26, and Edward Ide, 21, both died of CO poisoning on the fishing vessel Eshcol at Whitby in North Yorkshire on January 15 this year.
The pair had left the grill of a butane-fuelled gas cooker lit when they went to bed. The grill was being used to warm the wheelhouse and sleeping area, said the report from the Marine Accident Investigation Branch (MAIB).
The MAIB, which had published an interim report into the tragedy earlier this year, said in today's report:
:: The metal gauze in the grill was holed and corroded, causing extraordinarily high levels of CO emissions;
:: The cooker was four years old and had probably never been serviced;
:: The wheelhouse door and windows were closed and the sleeping area had no other means of ventilation;
:: No carbon monoxide alarm was fitted;
:: Neither the guidance for the installation of gas appliances on board small fishing vessels nor the cooker manufacturer's instructions had been followed when the cooker was fitted;
:: Prior to the accident, the deceased were extremely tired and cold;
:: The vessel was not equipped for overnight sleeping and the heaters provided on board did not work or were damaged;
:: The management of the vessel was ineffective.
The MAIB said recommendations had been made to the Maritime and Coastguard Agency which were intended to ensure that the accommodation areas in all small fishing vessels were fitted with a CO alarm.
MAIB chief inspector Steve Clinch said: "This is one of several fatal accidents recently investigated by the MAIB where fishermen or leisure boat occupants have been poisoned by carbon monoxide.
"Clearly, more needs to be done to raise awareness of the sources of the gas, its dangers and the precautions that must be taken.
"There is no question that the fitting of CO alarms in the accommodation areas of all small vessels would help to prevent further similar tragedies from occurring in the future."
A family whose children died from carbon monoxide poisoning on holiday have been granted legal aid for an inquest after an initial request for support was rejected.
Christianne Shepherd, seven, and her six-year-old brother Robert, from Wakefield, West Yorkshire, died after a faulty boiler leaked gas into their Corfu bungalow in October 2006.
Their parents Neil Shepherd and Sharon Wood were initially refused funding for legal representation at the inquest as lawyers are not usually required.
However, following a meeting with Prime Minister David Cameron and Legal Aid Minister Shailesh Vara, the family have now been granted legal aid.
Mr Vara said: "This is a very tragic case in which two young children lost their lives and my deepest sympathies are with the family, with whom the Prime Minister and I recently met.
"Questions remain unanswered and I have therefore authorised legal aid for representation at the inquest to hopefully provide much needed answers."
The two children were overcome by fumes from a faulty gas boiler while on a half-term holiday at the Louis Corcyra Beach Hotel in Gouvia.
Their father and his partner, Ruth Beatson, were both left in a coma as a result of the accident but survived.
Thomas Cook employees Richard Carson, 28, and Nicola Gibson, 26, were charged alongside nine Greeks with manslaughter by negligence in relation to the children and causing bodily injury by negligence to Mr Shepherd and Ms Beatson.
After a lengthy court case, three judges in Corfu found Mr Carson, a customer affairs executive, and Ms Gibson, a holiday representative, not guilty.
The judge pinned the blame on hotel manager Georgios Chrysikopoulos, head of the hotel technical department Petros Stoyiannos and hotel electrician Christos Louvros, who were each sentenced to seven years in jail.
A full inquest is due to take place next year.
We have been speaking to Carbon Monoxide campaigner Helen Carter from Sheffield about a storyline on Coronation Street, which was prompted by her concerns. Helen lost her husband after an unqualified person attempted to fix their boiler.
After seeing a similar scenario on the ITV soap Helen got in touch with the producers, who then decided to develop the storyline over the festive period.
Carbon Monoxide awareness campaigner Stacey Rodgers from Huddersfield has welcomed a storyline in Coronation Street highlighting the dangers of the silent killer. Her son, Dominic, was killed after a leak from a boiler in her neighbour's house.
She hopes the events in the soap make people consider getting a CO alarm.
A campaign's been launched to make people aware of the dangers posed by carbon monoxide poisoning in the run up to the Christmas period.
Labour MEP Linda McAvan is working with emergency services to highlight the threat posed and urge people to get a detector fitted in their homes. Use of additional heaters, doors with draft excluders and unserviced boilers can increase the threat to householders at this time of year
New research reveals that almost 3 million people in Yorkshire and Humber are still at risk from carbon monoxide poisoning. In many cases, this is likely to be because people mistakenly think that their smoke alarm will detect carbon monoxide.
The research comes on the day that carbon monoxide alarms become compulsory in new homes in Northern Ireland.
Stacey Rodgers and the Kirklees Carbon Monoxide Awareness Group are launching a new carbon monoxide campaign. Stacey's young son Dominic died from CO poisoning when fumes seeped into his bedroom. An inquest into his death was told a faulty boiler in a neighbouring property was to blame.
Dominic would have turned 19 this year and so the campaign is aimed at young people. It features a CO awareness film which has been developed by the staff and students of the Creative and Media School in Huddersfield.
The students have written, produced, starred in and edited the film as part of their studies. Its aim is to capture the attention of other young people on the brink of independence, alert them to the dangers of carbon monoxide and tell them how they can help keep themselves safe.