(CBS DETROIT) – As Canada plans to open its border to vaccinated Americans Monday, a labor dispute began at 6 a.m. on Aug. 6, slowing traffic.

Thousands of Canada Border Service Agency employees started a “work-to-rule” action, which has slowed the passage of commercial traffic attempting to cross the Ambassador Bridge into Windsor.

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There is also a long wait at the Port Huron border crossing.

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The unions representing border service workers are negotiating with the Canadian government over contracts.

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