Emergency breathing devices for suits worn by passengers during offshore helicopter flights weren't installed until nine years after they were first recommended and only after a helicopter crashed off the coast of Newfoundland in March, killing 17 people, an inquiry heard Monday.

The inquiry is looking into the safety of helicopters that specialize in transporting people offshore.

The suggestion to install breathing devices in the survival suits was made in a February 2000 letter written by the Canada-Newfoundland and Labrador Offshore Petroleum Board, a federal-provincial agency that manages development and exploration for oil and gas off the coast of N.L.

The board wrote to the Canadian Association of Petroleum Producers (CAPP), which represents 130 oil and gas companies in Canada and most of the companies involved in N.L.'s offshore oil industry, inquiring about the possibility of modifying survival suits by fitting them with emergency escape breathing devices.

The devices are small air cylinders that provide people with a small amount of air to breathe underwater in the event of an emergency, such as a helicopter being forced to ditch into the ocean.

"The results of research and experience indicate that the probability of successfully exiting an overturned helicopter in cold water is low even by passengers who have the benefit of escape training and an approved transportation suit," the letter states.

It goes on to say that the devices were being used by companies in the North Sea and were a significant step forward in reducing the risks associated with offshore helicopter travel.

In its letter, the petroleum board asked that the issue be discussed by CAPP and that the board be notified of the decision as to whether they'd be fitted on to survival suits.

The inquiry heard Monday that CAPP didn't finish modifying all flight suits to accommodate the device until May 2009, two months after Cougar Helicopters Flight 491 crashed into the Atlantic Ocean about 65 kilometres southeast of St. John's. The helicopter was carrying workers to the White Rose and Hibernia offshore oilfields. Only one of 18 passengers survived the March 12 crash.

The manager for the Atlantic Canada division of CAPP, Paul Barnes, was asked about the length of time it took to install the devices. He said there were many issues to deal with over the years, including selecting the correct breathing apparatus and addressing health and training concerns.

The inquiry into the safety of offshore helicopter transport, headed by Judge Robert Wells, a retired Supreme Court of Newfoundland and Labrador judge, began last month in St. John's. Earlier this month it heard from the lone survivor of the Cougar crash, Robert Decker, 28.