A dispute with potentially serious public safety consequences is brewing on B.C.'s Bowen Island, where volunteer firefighters are threatening to resign en masse if their new chief isn't fired.

Letters obtained by CBC News don't make it clear why the firefighters are unhappy with Chief Derek Dickson, but they say they don't believe their concerns can be addressed under Dickson's leadership.

"With great regret, the entire volunteer membership of the department (all 26 volunteer firefighters), will be resigning on Thursday, October 10, 2019 at 4 p.m. if Chief Dickson remains as the fire chief at that time," says a letter dated Monday and addressed to the municipality, which is located a short ferry ride from Horseshoe Bay on Vancouver's North Shore

On Wednesday, Bowen Island Mayor Gary Ander replied in writing to the department's letter to make it clear he had no intention of letting Dickson go, saying he was "very concerned and disheartened" by the threat.

"This ultimatum compromises our ability to meet our obligations related to the safety of the community and our obligations to our staff and volunteers," Ander wrote in his response.

He said the municipality is immediately bringing in a neutral facilitator to help build a "more constructive working relationship" within the department. He asked each firefighter to reconsider the decision to resign.

Volunteer firefighter Mike Hartwick leaves the Bowen Island Municipal Hall after a meeting with officials on Thursday. (Rafferty Baker/CBC)

When CBC visited Bowen Island on Wednesday, the firefighters, chief, mayor and chief administrative officer all declined to comment about the standoff.

Ander's letter says that Dickson was hired in July as the municipality invested more money in its fire department.

"He is exceptionally experienced and skilled and we are grateful to have him in this position and as a new member of our community," Ander wrote.

The department's former chief, Ian Thompson, retired after five years for personal reasons, which according to Ander, had nothing to do with issues at the fire hall.

On Thursday, talking to The Early Edition host Stephen Quinn, Ander said this is the first time in about 65 years the municipality has gone outside of the hall to find a new chief and there is "quite a culture there," so he expected some transition problems — but had no idea it would be this intense.

Firefighters 'taken aback' by training review

The firefighters say they first raised their unspecified concerns about Dickson in August, and then did so again in September, when they decided to end all practice and training sessions with the chief.

At a Sept. 30 meeting, the municipality's council voted to conduct an independent review of the fire department, Ander's letter says. The first phase would examine the training requirements mandated by the province.

The firefighters said they were "taken aback" by that news, writing that "collectively, we represent over 300 years of firefighting experience on Bowen Island." They maintain they have always been committed to training at provincial standards.

Ander said Thursday that he needs to find out if each member of the crew is up to date on their training. He said the municipality is liable if anything goes wrong during a fire and there is no training documentation on record.

"I hope that's not the case, but this is what we need to find out," said Ander.

Ander also said Thursday that it's the municipality's responsibility to find out what the problems are between the two sides and to take action if reconciliation is not possible — but he would not elaborate on what that action would be.

Despite the group's ultimatum, some volunteers have already said they do not plan to resign, Ander says.

"Any of you who wish to continue in your role are requested to advise us as soon as possible and to resume your participation in further practice and training sessions in keeping with the schedule prepared by the fire chief," the mayor wrote in his letter.

Ander's letter points out that volunteers will lose payments to their benefit plans if they quit, but "as a gesture of goodwill," the municipality will extend them for three months so they can find alternative coverage.

Read: Oct. 7 letter from firefighters

Read: Oct. 9 response from Bowen Island mayor