Three packages containing white powder were found yesterday in the mail by a worker at the Manhattan studios of liberal talk-radio station Air America, police said.

The employee made the find at the stations’ headquarters at 641 Sixth Ave.

The three packages - one of which was addressed to on-air personality Al Franken - contained a powder-like substance, which proved to be harmless.

* In Los Angeles, a man was charged yesterday with mailing more than a dozen letters containing white powder to Rep. Nancy Pelosi, Jon Stewart and other high-profile figures.

Chad Conrad Castagana, 39, appeared in U.S. District Court to face a two-count complaint of sending threats and sending hoaxes by mail.

Magistrate Judge Patrick Walsh ordered Castagana held without bail.

Soure: NY Post