Tests results of a white powder found in the Hart Senate Office Building shortly after noon Friday have come back negative for toxins.

“They’ve been declared safe,” a senior Senate aide said.

An aide in the Capitol Police Public Information Office said the department’s Hazardous Device Unit had responded to at least one incident and confirmed test results were negative for toxins.

According to an e-mail issued by the Senate Sergeant-at-Arms, a “white powdery substance” was found in Room 812. A later e-mail said Room 731 is also being investigated. Police did not evacuate the building during their tests.