FAIRBANKS - Packages filled with an unknown white powder arrived the offices of Sen. Mark Begich, Sen. Lisa Murkowski and Rep. Don Young on Monday, leading to the evacuation of the Federal Building in Fairbanks and heightened security at congressional offices in Anchorage.

The packages, however, were determined Monday evening to be harmless. Eric Gonzalez, the Alaska spokesman for the FBI, said that while they were “poorly packaged,” the bundles weren’t meant to be threatening.

“There was absolutely no criminal malice behind these packages,” he said, declining to elaborate on their contents.

Young said in a statement that his office had been notified by the FBI that the packages contained a mixture of concrete. He said it remained unclear why the material was sent.

Begich spokeswoman Julie Hasquet said an aide in the Fairbanks office opened an express-mail package from Arizona that morning and saw a white powder spurt out. The package was opened inside a plastic bag — a standard safety measure at the office — and there was never indication that the aide was in danger.

A similar incident happened at Young’s Anchorage office, according to his spokesman Luke Miller. When a package to the office was opened, a white substance was discovered inside, he said in an email.

A similar package was also discovered in Murkowski’s Fairbanks office, spokesman Mike Anderson said in an email, but it wasn’t opened. He said the Federal Protective Service seized the item.

The Alaska congressional delegation has offices in the same buildings in both Anchorage and Fairbanks.

The Federal Building in Fairbanks was emptied soon after the package was discovered at 11:22 a.m., Misewicz said, and Peterson Towers in Anchorage was being tightly monitored today.

Hasquet said the Fairbanks aide, who she declined to identify, was alone in the office when the package was opened. The aide remained under quarantine during the afternoon while tests were done to determine whether the unknown power was dangerous. She was taken to the hospital, but Hasquet said she had been released by that evening.

In Fairbanks, two fire trucks and an apparent hazardous materials unit were outside the Federal Building at about 2:30 p.m. Personnel at the site had been evacuated earlier, and only about a half-dozen cars remained in the parking lot.

Assistant Fairbanks Fire Chief Ernie Misewicz said the Fairbanks North Star Borough’s hazardous material team and Eielson Air Force Base Fire Department were requested to help identify the powdery material. Since the incident occurred in a federal building, the FBI is also part of the investigation.

Miller said Young’s Anchorage office worked with the Federal Protective Service and the Anchorage police and fire departments as they investigated the incident. He said the staff was pleased with the timely response to the incident.

Misewicz said the Federal Building would be open for normal business today.

Congressional offices have been on alert for packages containing powdery substances for the past decade. The offices of two U.S. senators, Tom Daschle and Patrick Leahy, were targeted with powdered anthrax in 2001, soon after the Sept. 11 attacks. Five people died in anthrax incidents at the time, which also targeted various media outlets.

Murkowski said congressional staff are thoroughly trained to identify suspicious mail and open it safely. Mail delivered to Washington, D.C., offices is even irradiated before it is opened, she said.

Contact staff writer Jeff Richardson at 459-7518.