Initial testing of the white powder found in envelopes in a mailroom at a federal building in lower Manhattan reveals a substance similar to Boric acid, according to a senior official familiar with the matter.

A New York City building housing an Immigration and Customs Enforcement facility was evacuated after unknown white powder in multiple envelopes was found at the complex, authorities announced on Thursday.

Mayor Eric Adams said he was aware of the situation unfurling at 26 Federal Plaza and New York Fire Department hazmat teams were on site to ensure safety.