Officials with Canada's Department of National Defence say one of its vessels in the Strait of Georgia — HMCS Calgary — spilled 30,000 litres of fuel on Saturday morning.

The patrol frigate was sailing in the strait's shipping lanes between Nanaimo and Parksville when the spill occurred, said Commodore Jeff Zwick, commander of the Canadian fleet in the Pacific region.

"We take environmental stewardship very seriously and we're working proactively to address this as quickly as possible," Zwick told a news conference at CFB Esquimalt on Sunday afternoon.

On Feb 24, <a href="https://twitter.com/hashtag/HMCSCalgary?src=hash&ref_src=twsrc%5Etfw">#HMCSCalgary</a> reported a fuel spill of approx. 30,000L while at sea. We are coordinating with <a href="https://twitter.com/environmentca?ref_src=twsrc%5Etfw">@environmentca</a>, <a href="https://twitter.com/CCG_GCC?ref_src=twsrc%5Etfw">@CCG_GCC</a>, <a href="https://twitter.com/Transport_gc?ref_src=twsrc%5Etfw">@Transport_gc</a> and EMBC to ensure necessary actions are taken and information gathered to support further investigation. <a href="https://t.co/OZlBhanTLS">https://t.co/OZlBhanTLS</a> <a href="https://t.co/GkILK7oWSP">pic.twitter.com/GkILK7oWSP</a> —@MARPAC_FMARP

The spill happened while crews aboard the vessel were transferring fuel internally. Zwick said about 30,000 litres of F-76 fuel was spilled. He said human error was likely a factor, but noted the investigation into the cause is still underway.

F-76 is a naval fuel used in compression ignition engines, according to a NATO publication. It's also used in naval gas turbines and ships' boilers for steam raising.

Zwick said the fuel is similar to kerosene, lighter than water and quickly evaporates.

"This fuel historically does not provide a significant effect to marine life," he said.

'No slick or sheen'

Tracy Cornforth, who speaks for safety and environment with the Canadian navy, said it would be unusual for the fuel to remain in the water or combine with sediment in the ocean.

"You don't find any kind of sheen or slick in the marine environment just due to the nature of the fuel and the fact that it readily evaporates so quickly," Conforth told the news conference.

Zwick said crews onboard were alerted to the spill after an overflow valve sounded an alarm. He believes the fuel was slowly trickling out, and described the total amount as a small percentage of what was aboard HMCS Calgary.

He said the crew corrected the problem that was causing the leak, then reversed course to look for the spilled fuel. "Once Calgary discovered that she had a difficultly, she took all the right steps in responding to the problem," he said.

We hope that the response was well done & look forward to further information. We do know that this type of fuel, as noted in the story, dissipates quickly and can't be recovered in any meaningful way. That human error may be the cause is the greatest concern - we were lucky. —@GeorgiaStraitBC

The Canadian Forces is working with Environment Climate Change Canada, the Canadian Coast Guard, Transport Canada and BC Emergency Management to assess its impact.

Further shoreline searches

Crews plan to search the shoreline Monday for areas along the vessel's route, including the Southern Gulf Islands.

The Canadian Forces has asked local airlines, BC Ferries and the public to look for signs of the spill and report them to the the Defence Department's Regional Joint Operations Centre at 250-363-5848.

Earlier this week, the vessel posted on its Twitter feed about conducting exercises in unusual snowy conditions on B.C.'s West Coast.