VANCOUVER, July 27 (Reuters) - Canadian border guards and customs officials voted on Tuesday to go on strike just days before fully vaccinated U.S. citizens and permanent residents will be allowed into Canada, unions representing the workers said, a move that could potentially cause disruptions and hurt businesses emerging out of the pandemic-driven economic downturn. A strike would slow down commercial traffic at the land border, the unions said, as well as impact international mail and collection of duties and taxes. But a spokesperson for the Canada Border Services Agency (CBSA) said 90% of employees have been identified as "essential" so will continue to work in the event of a strike. Last week, Canada announced plans to allow fully vaccinated Americans on Aug. 9, and fully vaccinated international travelers starting on Sept. 7. The border has been shut for non-essential travel for more than 16 months because of the coronavirus pandemic. read more The Public Service Alliance of Canada (PSAC) and the Customs and Immigration Union (CIU) said in a joint statement that strike action could begin as soon as Aug. 6 after 8,500 members voted in favor of the action. Contract talks reached an impasse in December 2020, the unions said. Prior to the pandemic, tourism was the fifth-largest industry in Canada, contributing C$105 billion ($83.4 billion) to the GDP and providing one in ten jobs, according to the Tourism Industry Association of Canada. Corinne Pohlmann, senior vice president of national affairs for the Canadian Federation of Independent Business, said a strike would compound issues faced by small businesses throughout the pandemic - slow shipping times, lack of customers, rising costs. "It"s not favorable at all for a lot of small businesses relying on either goods coming across the border or people coming across the border," Pohlmann said, calling the timing of the strike "extremely unfortunate." But CIU President Mark Weber told Reuters that the union didn’t plan this strike to coincide with the reopening of the U.S. border, pointing out that the unions began the strike vote "before we even knew what day the borders would be opening on." Weber is still hopeful they’ll be able to make a deal with the federal government without going on strike. Their demands include higher pay, the ability to carry their guns in areas like airports and to address issues of "toxic" workplaces, he said. The federal government is "disappointed" that PSAC rejected a "fair offer for its members," but remains "open to returning to the bargaining table at any time," a government spokesperson said in an emailed statement. CBSA spokesperson Judith Gadbois-St-Cyr said officers have proven their resilience since the beginning of the pandemic by helping to prevent the spread of the virus and its variants. "We expect that our officers will continue to fulfill their duties with the highest level of integrity and professionalism." ($1 = 1.2592 Canadian dollars)