The Hamilton County Board of Elections administrative building in Norwood was evacuated Saturday, Oct. 24, after a worker found a suspicious substance in the mail.

The discovery happened around 10:50 a.m. at the building on Smith Road, according to Fox 19. A poll worker opened an envelope containing white powder while sorting absentee ballot applications, WKRC reported. Police and hazardous materials crews responded, evaluated the substance and cleared the building for re-entry.

No one was injured.

The evacuation affected only the administrative building, not the Early Voting Center. Voters continued casting ballots without interruption, and the center stayed open through its regular 4 p.m. close, Board of Elections spokesperson Stacey Moher told Fox 19.

Sherry Poland, director of the Hamilton County Board of Elections, and Deputy Director Raquel Burgos said in a statement that the safety of employees and the public was their "highest priority."

"I'm always so proud of the bipartisan team here at the Board of Elections. Everyone remained calm. They followed our evacuation procedures," Poland told WKRC.

The identity of the substance has not been confirmed. The FBI is investigating, according to WKRC. Fox 19 reported that details remain under investigation.

The Hamilton County incident follows a wave of suspicious mailings targeting election offices and members of Congress nationwide. The Guardian reported that more than three dozen members of Congress received suspicious letters, according to The Hill. Ohio Secretary of State Frank LaRose said the U.S. Postal Service intercepted a similar letter addressed to his office. LaRose said tests in other states found the powder was not harmful but urged all 88 Ohio counties to stay alert.

Poland said early in-person voting in Hamilton County has already surpassed the last midterm's total, with more than 40,000 voters compared to about 34,000 in the prior cycle. Extended hours begin the week of Oct. 26, with the center open 7:30 a.m. to 7:30 p.m. most days and until 8:30 p.m. Tuesday, according to WKRC. There is no in-person voting Nov. 2.

Voters can check registration, precinct information and sample ballots at votehamiltoncountyohio.gov.