MOUNTAIN VIEW (CBS SF) – Amid growing concerns worldwide about the newly-discovered Omicron variant, Google announced that it is again pushing back return-to-office plans.

Security VP Chris Rackow told employees in an email Thursday that plans to switch to a hybrid work model for U.S. locations on January 10 have been delayed, CNBC reported. Rackow said it would wait until the start of the New Year to assess when offices could safely return to a “stable, long-term working environment.”

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The company said it would allow specific locations to determine their timelines to return employees back to the office.

While employees are no longer required to return to offices on January 10, Rackow said the company is still encouraging workers to come in “where conditions allow.” Google said 90% of U.S. offices have reopened and that 40% of the company’s U.S. workforce have come into the office in recent weeks.

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First discovered in southern Africa last month, the first U.S. case of the variant was detected Wednesday in a San Francisco resident who recently traveled. Cases have also been found in several other states as of Friday.

In August, CEO Sundar Pichai had pushed back the return-to-office date from October to January as the country saw a surge in cases due to the Delta variant over the summer.

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“The COVID-19 pandemic has been a humbling challenge for all of us and I continue to be impressed by the way our teams are navigating through it,” Pichai said at the time.