CHICAGO (CBS) – The NATO summit has prompted some downtown businesses to tell their workers to stay home to avoid potential problems.

Increased security, street closures and uncertainty about protests has companies such as Blue Cross/Blue Shield telling its workers to telecommute on May 18 and 20.

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John Challenger, CEO of the outplacement firm Challenger , Grey & Christmas, says he’s heard of companies trying to get as much work done ahead of time, in case of problems.

Challenger says his firm is scheduling meetings in its suburban offices and encouraging telecommuting, which has become commonplace for some already.

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Attorney Kathleen Holthaus works for Sidley & Austin located at 1 S. Dearborn says she’s choosing to spend at least one day at home to avoid the hassles of a commute into the downtown.

Those who choose to report to the office must endure increased security. The revolving doors will be locked, and occupants will need a key card to get on the elevator.

The Marquette Building is one of several that has installed shatter-proof film on the inside and outside of every window.

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