The package sent to Begich's office was partially opened, said Julie Hasquet, the senator's press secretary.
Young's office said in a statement that a white powder was discovered when the package sent to his office was opened by a staffer.
Discovery of the packages prompted closure of the entire Fairbanks federal building, where the senators have their Fairbanks offices.
Young was not at the Anchorage office when the package was discovered, he said.
This afternoon the offices of our state delegates, Lisa Murkowski, Mark Begich, and Don Young, received suspicious packages in the mail.
The first package was reported in Fairbanks, at the Federal Building, where each of the delegates maintain an office. The office promptly turned over the package to Federal Marshals who also have an office in the building.
Meanwhile, in Anchorage, the Office of Don Young, located in the Federal Building, also received a suspicious envelope post-marked from Arizona. The FBI informed the Young office that the substance is a concrete mix and not hazardous, they also stated, "it is not clear at this time why the package with the concrete mixture was sent to Congressman Young," this according to Young's office.