After a week of asserting its employees should not be subject to federal health advisories surrounding COVID-19, Canadian Pacific Railway has reversed course and ordered workers who have travelled abroad to stay home — but some are worried the damage has been done.

"Employees that work for this railway are quite nomadic and we end up in a lot of different facilities throughout the country," an anonymous union official told CBC News. "The biggest concern is, how much are we spreading by remaining in the workplace?"

Over the past week, CP Rail required dozens of workers who'd travelled out of the country on holiday to report for work, despite federal health advisories issued March 13.

In its advisory, the federal government said an exemption should be provided to workers who are essential to the movement of goods and people.

But when union officials reached out to Transport Canada, they were told the exemption referred to daily travel in the course of doing business and not the initial return from vacation.

"When people return from a vacation or personal trip from outside of Canada, the advisory [requires] them to self-isolate for 14 days," reads an email from Transport Canada. "After returning to work, they can then be exempted if their day-to-day work requires them to cross the border and come back to Canada."

That email was forwarded to Mark Redd, executive vice-president of operations with CP Rail, who responded the following day.

In a letter, Redd says CP interpreted the exemption to apply to workers critical to the operation of the railway, not just to those crew members who cross the border as part of their duties.

"We were supported in this position in discussions with government officials," Redd said. "We see, however, that [Transport Canada] has since advised you that the exemption should not apply to a worker returning from a vacation or a personal trip to the U.S. Thank you for sharing that communication with us."

Redd said CP was revising its position in light of the situation and would compel all workers returning from trips outside of Canada to self-isolate.

"In an unprecedented health crisis, such as we are facing with COVID-19, there are going to be good faith differences of interpretation," Redd said.

A spokesperson with CP Rail confirmed two employees at the company's Calgary headquarters had tested positive for COVID-19.

Worker complaints

In the week since the federal advisory was issued, staff and rail unions have complained — with many voicing fears that workers across the network have been exposed or put at risk.

"Half [of us] are relieved and happy [at this change], knowing that there's a much smaller chance of any transmissions and they can feel safer coming back to work," the union official said. "The other half are now concerned and realize that the government has taken this seriously.

"There is potential that people that were in the workplace earlier this week could potentially be carriers and have now spread that infection through the workplace."

In response to a request for comment from CBC News, a CP Rail spokesperson said the company was now abiding by recommendations from the federal government, including requiring employees who return from trips outside of Canada to self-isolate.

"Initially, CP received conflicting interpretations of the government of Canada's exemption. As soon as we were made aware of the conflict, we sought clarification and then adjusted," the spokesperson said.

In a letter sent by CP CEO Keith Creel on March 19, staff were informed of the changes and the new order for any worker returning to Canada on or after March 13 to self-isolate for a 14-day period, regardless of whether or not they exhibit symptoms.

But some employees are frustrated that the change took this long to implement.

"The idea that they're coming in now and doing such an extensive clean of the facilities where people had travelled shows that the company is also concerned with that," the union official said.