A years-long struggle with bats led the federal government to relocate 160 staff in a national capital region building until the problem was dealt with, according to documents released to CTV News.

Staff at Indigenous and Northern Affairs Canada started complaining in 2014 that they had spotted bats winging their way around the third and sixth floors at 15 Eddy St. in Gatineau, just across the Ottawa River from Parliament Hill.

"The bats were back this a.m.," a September, 2014 email says in the subject line.

In another email contained in a package released under federal Access to Information laws, an official noted there were seven bats spotted in one week in August, 2014.

Another staffer laid out his concerns after seeing one of the mammals in his workplace.

"This morning there was a bat flying around the office and at employees," the civil servant wrote in an August, 2015 email. "These are wild animals that could be carrying harmful diseases."

In March, 2016, 160 employees moved to another building in Gatineau. The move cost approximately $30,000, a spokeswoman from INAC wrote in an email to CTVNews.ca. The department declined an interview request.

"Employees were relocated due to the situation, to ensure employee well-being," Valérie Haché said in the email.

Bat spotted at new building

But the employees weren't entirely able to escape the flying menace: a bat was spotted in early January at the new 10 Wellington St. location, a spokesman from Public Services and Procurement Canada said in an email.

"Patrols of the building are conducted daily from May to November and weekly from December to April to monitor; however, bats are sporadically seen. The patrols are done early morning by a Brookfield Global Integrated Solutions (BGIS) building technician who is also a certified pest control technician," Nicolas Boucher wrote, referring to the building management company.

All floors at 15 Eddy are currently occupied, despite a September, 2016, bat sighting, officials said.

By last fall, managers were dealing with the fears of potential new occupants, according to an email with the subject line "Health concerns and moving to 15 Eddy 6th floor -- referred to by many as the 'bat' floor."

"My understanding is that Education [the section that had previously occupied the floor] was removed from this floor due to the bats and from what I saw, there has been nothing done in regards to reclamation," one civil servant wrote last October about her concerns.

Only one or two bats seemed to have been spotted at any time, and daily checks rarely turned up any sightings, according to a series of emails included in the documents.

Bats were disease-free

Employees were instructed not to try to catch the bats, but to call Public Services to have them captured and released. They had an exterminator look at the problem as early as August, 2014, but determined extermination would not be effective because additional bats would get in through the holes in the building's facade. In addition, one of the captured bats is the species known as a little brown bat, which is protected as endangered under Canadian species-at-risk laws.

The sightings seemed to stoke fear in some employees.

"The presence of bats in a workplace can result in air quality issues (hazards) that can have a very negative impacts [sic] on employees' health," one policy analyst wrote to her manager.

"Will you please advise if the bat found in our office today has been sent to CFIA [the Canadian Food Inspection Agency] for rabies testing? Will you also please advise if 15 Eddy, 6th floor, will be inspected for the presence of bat droppings, and if found what will be done to abate this hazard?"

Despite the complaints by staff, it doesn't appear they were in any danger. All of the bats captured by workers were disease-free, according to testing by Quebec's forestry ministry, Brookfield wrote in a 2015 report.

The Public Health Agency of Canada's national advisory committee on immunization says the risk of rabies is extremely rare in cases with no obvious human contact with a bat. PHAC recommends medical intervention only when "there has been direct contact with a bat" and "a bite, scratch, or saliva exposure into a wound or mucous membrane cannot be ruled out."

"At this time, there [is] no immediate threat to employees as the live bat was captured and released outside," an occupational health and safety manager noted in response to the rabies concerns in an Aug. 26, 2014 email.

"It is not uncommon to find bats in buildings and in the attics of homes at this time of year (their non-hibernating stage)," she wrote.

"At this time, there is no indication we are dealing with an infestation," she added in an email later that day.

Situation 'resolved'

The INAC spokeswoman didn't answer a question about why staff were relocated when all evidence suggested there was little to no risk to their health.

By the summer of 2016, the complaints made their way to the office of Indigenous Affairs Minister Carolyn Bennett, whose staff sought a briefing on the matter last August.

The bat problem seemed to stem from holes in the building's brick work, according to a consultant's report. INAC was already undergoing work on its facade, and the consultant recommended installing special mesh over holes that would let bats exit the building but not re-enter, leading Brookfield to conclude the problem would diminish once the work was complete in September, 2016.

"All holes identified during last year's inspections were filled with a special anti-bat netting. Every summer and fall, a brick survey inspection is performed that identifies any holes," Boucher, the spokesman for PSPC, wrote Tuesday.

The floor is occupied again. The INAC spokeswoman said employees moved onto the floor "when the situation was resolved."

Emails and phone calls to Brookfield, requesting an interview, were not returned.