The Postal Service is seeking a temporary exemption from President Joe Biden’s vaccine-or-testing mandate, arguing a waiver would prevent major disruptions to mail delivery.

The request comes just days before the Biden administration’s rule is slated to take effect, and as the highly transmissible omicron variant sidelines workers in various parts of the economy.

Deputy Postmaster General Douglas Tulino wrote in a Jan. 4 letter to the Occupational Safety and Health Administration that requiring Postal Service workers to comply with the new rules “is likely to result in the loss of many employees — either by employees leaving or being disciplined.”

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