Sen. Jose Peralta’s Queens office was shuttered Monday when a staffer found suspicious powder in an envelope.

“The whole thing was strange,” said Chris Sosa, a spokesperson for Peralta.

It’s unclear how the envelope — which for some reason was addressed to Sen. Michael Gianaris — ended up at Peralta’s East Elmhurst office.

Sources said Peralta’s chief of staff opened the package with the green-colored powder at about 4 p.m. She was given a slew of tests and deemed okay, Sosa said.

“Everyone was a little shaken up given the current climate,” Sosa said.

Police said the substance wasn’t hazardous or explosive but is being sent for further testing.

The Queens office will remain closed Tuesday.