By Dana Bash and Theodore Schleifer

FLORIDA (CNN) — Marco Rubio’s aides were evacuated to the roof of their Washington headquarters Tuesday after a powdery substance was found in a piece of mail addressed to the campaign.

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A Hazmat team came and evacuated the campaign’s offices and sent employees from the ninth-floor of their nine-story building to the roof, according to a Rubio aide. As of late Tuesday afternoon, fire crews were wrapping up and the staffers were being allowed to return to the office.

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Earlier this month, Hazmat and local authorities were called to Ted Cruz’s campaign headquarters in Houston after their office received a letter accompanied by a white substance, the campaign said at the time. Authorities said it was not toxic. The Florida senator early Tuesday evening provided an update on Twitter: “Glad campaign staff in DC is all safe! Thanks to DC emergency personnel.”

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