An envelope filled with white powder was mailed Monday to the South Portland office of U.S. Citizenship and Naturalization Services.

The Portland Press Herald reports that an employee who sorts mail at the office on Gannett Drive noticed the powder when it leaked from the envelope. The South Portland Fire Department was notified about 1:20 p.m.

A subsequent test revealed that the powder was harmless, and the building was deemed clear about 3 p.m., the Portland newspaper reports.

A spokesman for the South Portland Fire Department declined to say whether the envelope included a message, the Press Herald reports.

The office of Citizenship and Naturalization Services handles requests for immigration benefits, screens refugee applications and welcomes new citizens at naturalization ceremonies, according to the agency’s website.