Inadequate ventilation, poor maintenance and old equipment are being blamed for causing a buildup of potentially hazardous airborne mould aboard Canada’s most advanced warships, newly released Defence Department documents show.
The department’s Directorate of Force Health Protection says an air quality assessment aboard HMCS Winnipeg found higher-than-normal levels of mould spores in three compartments while the frigate was sailing from Tokyo to Hawaii in July 2017.
The findings are important because some sailors have long complained of health problems they say could be related to mould exposure while serving aboard Canada’s 12 Halifax-class frigates.
The navy asked for the assessment to identify potential hazards that could affect the health of crew members. Commissioned in the early to mid-1990s, the Canadian-built warships typically carry a crew of 200 to 250.
Airborne mould concentrations aboard Winnipeg were found to be above background levels in an air conditioning plant, the ship’s solid-waste handling plant and an equipment room near the helicopter landing pad.
The report says the mould found in the waste plant was likely caused by liquid waste sliding down the side of a compactor during operation. High levels of humidity were also recorded in all three locations.
In all, 20 compartments showed some accumulation of dust or mould.
While there are no standard exposure limits for airborne concentrations of mould or mould spores, the December 2017 report says mould is hazardous for people with compromised immune systems or mould allergies.
The Royal Canadian Navy should improve the ships’ ventilation and require more frequent cleaning and inspections of ducts and filters, the report says.
A report from March 2015 — prepared by the engineering firm Bronswerk — found the frigates’ ventilation and air conditioning systems had “significantly degraded” because of a lack of maintenance, leaving the equipment “old and unsupportable.”
However, other internal documents released this week under the Access to Information Act indicate the navy has taken steps to deal with its ongoing mould problems, which has included new cleaning instructions and upgrades to some equipment.
Aside from airborne mould, the 2017 assessment also found mould growing on some surfaces.
“Undisturbed mould was detected above background levels in limited number of low-occupancy compartments, some of which — like the potato locker — are prone to mould growth,” the report said.
“Nonetheless, visible mould growth should be removed and relative humidity lowered in the identified compartments to prevent mould growth.”
The report includes photos showing mould on insulated pipes inside an air conditioning system, at a duct joint in the crew’s lounge washroom, above the fan in the fruit and vegetable store, and on beams in the ceiling in the potato locker. Yeast was also found growing on a bulkhead near the wardroom.
Other photos show a buildup of dust and mould around several vents.
A health hazard assessment team took samples to measure for other contaminants, including dust, fuel vapours and a long list of chemical compounds, such as carbon monoxide, carbon dioxide and volatile organic compounds. No serious problems were found with these contaminants.