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.

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.

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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