TORONTO — Canadians could be facing slowdowns at the border with the United States next month after members of a union representing about 9,000 Canadian Border Service Agency employees voted in favour of striking, jeopardizing the federal government’s reopening plans.

The Public Service Alliance of Canada and its Customs and Immigration Union announced Tuesday its members may strike as soon as Aug. 6, three days before fully vaccinated U.S. citizens will be able to visit Canada without having to quarantine for two weeks.

On top of allowing fully vaccinated U.S. citizens to visit Canada starting Aug. 9, the government also plans to open the country’s borders to travellers from other countries who are fully vaccinated on Sept. 7.

PSAC-CIU represents 5,500 border services officers, 2,000 headquarters staff and other workers at Canada Post facilities and in inland enforcement jobs.

Strike action could cause significant delays in courier and travel services, Chris Aylward, national president of Public Service Alliance of Canada, told reporters Tuesday.

“We’ve been in negotiations for over three years, but the employer has flat out refused to address critical workplace issues impacting our members,” Aylward said.

The union is now calling on Treasury Board President Jean-Yves Duclos, Public Safety Minister Bill Blair and CBSA president John Ossowski to return to the bargaining table.

The members employed by the CBSA and Treasury Board began holding strike votes in June, after they had been without a contract for nearly three years and talks broke off between the two sides in December. They voted “overwhelmingly” in favour of a strike, Aylward said, but an exact number was not revealed.

The union and the employers have been unable to agree on better protections for staff that the union argues would bring them in line with other law enforcement personnel across Canada and address a “toxic” workplace culture.

CBSA employees have been without a contract since 2017 and in that time, the union has been negotiating for protections against excessive discipline and harassment, whistle-blowing protections and remote work provisions.

The union warns that the ongoing labour dispute could cause a significant disruption to the flow of goods, services and people entering Canada because traffic at borders may be slowed, while mail and the collection of duties and taxes will be impacted.

CBSA spokesperson Judith Gadbois-St-Cyr said in an emailed statement that 90% of border services officers have been identified as essential and will continue to work at their jobs. She added that the agency “will respond quickly to any job action/work disruption in order to maintain the safety and security of our border.”

Weber said those who work during a strike would only need to carry out their “essential” duties. The union doesn’t yet have a plan for what a strike would look like but he added that they may use work-to-rule or rotating strikes if one is called.

The Treasury Board and the Public Safety Department have yet to respond to a request for comment.