You can hear the frustration in Rod Corea's voice.

For years, the oil-fired appliance expert, hired by the Yukon government, told officials about the poor and sometimes dangerous state of oil heating systems in the territory.

"I assumed it was so painfully obvious that something would be done,” he said Friday at the coroner's inquest into the deaths of five people from carbon monoxide poisoning.

After completing five reports from 2007 to 2010, Corea had enough.

"I had to stop coming back ... my moral outrage would have kicked in,” he said, testifying over the phone.

In his final report, completed in 2010, Corea found only four of 305 heating appliances inspected were up to code.

That's nearly a 99 per cent failure rate.

In the conclusion of that report, he makes an ominous prediction.

"The evidence — especially from the current survey regarding problems at re-inspected sites and new installations — strongly indicates that action must be taken as soon as possible to prevent an incident causing harm to person or property.”

Two years after that report was written, five people died.

Bradley Rusk, 45, his wife Valerie, 37, along with their children Gabriel, 13, and Rebekah, 11, died in their rented Centennial Street home in January 2012 along with 47-year-old family friend Donald McNamee.

An inquest into their deaths was called last week to try to come up with recommendations to prevent similar deaths in the future.

Corea was the last witness to testify and the jury made its recommendations late Friday afternoon (see story below).

In Ontario, where Corea is from, oil-burner mechanics have the authority to shut down heating systems if they believe they are unsafe.

In his 2007 report, Corea would have shut down 10 per cent of the systems he saw. By 2010, that number was 17 per cent.

As it was, all he could do was provide reports to the homeowners about the problems he found.

"That's all I could do ... make very strong suggestions,” he said.

Corea testified he never saw the heating system at the Rusk house as part of his inspections.

A crumbling, inappropriately-sized chimney connected with the heating system at the Porter Creek home led to the build-up of ice, soot and debris which eventually blocked the deadly gas inside, experts testified earlier in the week.

Corea called the tragedy "preventable.”

Along with the five reports, Corea also completed a DVD presentation, which he said he believed was going to be distributed to top government officials.

During his time in the Yukon, he never met with ministers or high-ranking bureaucrats, he said.

Corea was called as a witness by members of the Rusk family. He said he was glad to be able to participate to share his "outrage and frustration.”

"My condolences for your loss. I wish I could have done more,” he said.