The economic impact of the Boston Marathon bomb suspect manhunt could run into the billions of dollars, according to one expert, as a million city residents were stuck at home, stores were shuttered and public transit ground to a halt.

Boston businesses were advised to remain closed, city employees were told to stay home or remain in place at work, vehicular traffic was limited and travel into the city via Amtrak and discount bus lines was suspended.

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As a result, food, supplies and even the gasoline required for the city to get back to business wouldn't make it into Boston for the duration of the lockdown, said Michael Barrett, former director of strategy for the White House Homeland Security Council.

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"Every city has three days of fresh food on average," Barrett told “Big Data Download.” "There's only so much excess capacity in the supply chains.”

The Boston Marathon bombing will also have a ripple effect on the city's economy going forward, he said. Increased security at public events of any size will require additional local and state police forces, Barrett said, and that overtime can grow expensive.

-- Matthew DeLuca contributed to this story.