A former sailor who served for almost a decade has been diagnosed with a debilitating lung condition, which his civilian doctor and now Veterans Affairs attribute to his exposure to mould and possibly diesel fumes aboard two navy destroyers, CBC News has learned.

The case of retired lieutenant Alan Doucette, 36, who now lives in Moncton, N.B., may have far-reaching implications for the military, which began last week to institute a series of health hazard air quality checks aboard its patrol frigates.

Last year, a CBC News investigation documented how the navy has struggled for years to deal with the blight in the ventilation systems aboard its recently refurbished warships.

The new set of tests, which started aboard HMCS Winnipeg on July 15, will eventually be conducted fleet-wide.

A deployable health hazard assessment team is trying to determine if engineering fixes to the heating, ventilation and air conditioning system have controlled or mitigated the mould problem.

Battling the blight is an age-old concern for any warship.

Senior navy officials have insisted that whenever mould is found it's cleaned up and, more importantly, there have been no reports of health issues.

But Doucette says, in his case, the suspicion that poor air quality, specifically mould exposure, was behind his condition was documented by a civilian specialist in Halifax and was presented to military doctors as far back as 2009.

He was medically released from the navy in 2012 after being deemed unable to deploy.

A pair of now retired destroyers, HMCS Iroquois and HMCS Athabaskan, were full of mould, Doucette said, adding he first reported his breathing difficulty and health concerns in 2007.

"There was extensive mould, I noticed, in the bulkheads, in the joints," Doucette, a former maritime warfare officer, told CBC News. "It was pretty much dripping down the walls and on the ceiling."

He said he's convinced mould, rather than diesel fumes, was the biggest factor because it was often present in the sleeping quarters and parts of the ship he frequented.

"There was black mould pretty much in all the living quarters," Doucette said. "It's taken seriously in civilian life, but apparently they didn't take it seriously for the military. I invested the best 10 years of life up until I got sick and they kicked me out."

Health risks

Experts say short-term exposure to mould can cause nasal and sinus congestion, coughs, as well as sore throats. It has been linked to asthma, nosebleeds and upper respiratory tract infections.

There is divided opinion in the medical community about long-term exposure, but some studies in the U.S. have suggested it can affect not only the lungs but the central nervous system, and lead to memory loss.

A photo of a mould-encrusted fixture near a ventilation shaft aboard the now retired HMCS Athabaskan was taken in the summer of 2011. (CBC )

Pat McLaughlin, a retired chief petty officer who has been raising the alarm internally for years, has said many warship crew members leaving port expect to get sick on deployment.

Crew members routinely complained of what they called the "AC flu" and the "CPF hack," he said.

Doucette said his civilian doctor referred to him as the "canary in a coal mine" when it came to mould.

'This is not an allergy'

His military medical records, which he shared with CBC News, say his "exposure to fumes" was the cause of his health trouble, but the subsequent examination by a civilian specialist at the respirology clinic of the Halifax Infirmary noted the presence of mould as a likely cause.

"This is not an allergy," said one doctor's report, which noted his condition was likely the result of long-term exposure to "diesel fumes and mould."

Veterans Affairs agreed with the assessment, stating Doucette suffered from hyper-reactive airway disorder related to being around "volatile organic compounds."

Doucette said he knows others who have suffered the same respiratory illness, which include a debilitating cough and trouble breathing.

Since the original story last year, CBC News has separately documented claims by half a dozen serving members who claim mould exposure has made them sick.

Most were not prepared to share medical records, and all of them asked that their names not be used. Talking to the media was, as one sailor in Halifax put it, "a career-limiting move."

A civilian contractor watches as condensation and humidity buildup in the engine room of HMCS St. John's pours on to an electrical panel during an October 2011 inspection of the warship's ventilation system. (CBC)

Commodore Jeff Zwick, the commander of Canada's Pacific fleet, urged anyone with health worries to step forward.

"We have always taken these concerns very seriously," Zwick said in an interview with CBC News. "Our primary concern is to ensure that we have a safe and healthy environment for all of our sailors, which is why when we have instances of mould that we take very quick, immediate steps to address the issue."

Air quality assessments are routinely conducted aboard each warship, he said.

The navy made the same claim last year when the issue was first made public.

CBC News asked, under Access to Information legislation, for copies of those inspection reports and studies related to potential air quality health hazards.

Almost nine months has passed and National Defence has yet to release the documents. As of late last week, it could not say when they would be available.

Moisture buildup

The problem of mould aboard the navy's frigates has been potentially acute and was flagged as concern in 2011 aboard HMCS St. John's.

An inspection by an independent contractor found the precision air-conditioning units "were not effectively dehumidifying the ship."

That, according to the assessment report, created a gushing buildup of moisture within the system, which led to "conditions for harbouring respiratory bacteria" and "potential crew-wide health issues."

The problem was not dealt with during the multibillion-dollar midlife refit of the country's 12 frigates, which recently concluded.

The Halifax-based frigate HMCS Montreal. The navy is conducting air quality assessments aboard each of its warships after concerns about mould in the ventilation were raised. (Adrian Wyld/Canadian Press)

Instead, the navy chose to institute a separate two-step engineering fix on the heating and cooling ventilation system, which Zwick said has shown results.

"Every indication we have today is that it has worked to improve the system," he said.

All 12 warships have gone through the first stage of the modifications, which allow for better moisture drainage from the air conditioning unit.