A suspicious piece of luggage led to the shutdown of parts of Minneapolis-St. Paul International Airport on Tuesday afternoon, delaying flights, shutting off vehicle traffic to the airport and forcing passengers to evacuate part of the baggage claim area at the Lindbergh terminal.
The Transportation Security Administration shut down three security checkpoints, the north end of baggage claim and a couple of concourses for more than an hour as a bomb squad examined the luggage a bomb-sniffing dog had flagged, TSA spokeswoman Carrie Harmon said. Vehicle traffic into the airport was also shut off.
The all-clear was given after the bomb squad discovered the luggage posed no threat, she said.
Airport spokesman Patrick Hogan said the luggage turned out to be an empty bag that's used by the airline to mark the last bag coming off a flight.
"We'll probably never know what it was" that the dog detected, Hogan said during a media briefing at the airport.
Canine teams occasionally do raise false warnings while screening luggage, said the TSA's Harmon, but she added it's necessary to follow up on all those leads. "Out of an abundance of caution, if a dog alerts on an item, then we need to thoroughly check that item out with the assistance of the bomb squad," said Harmon.
"If a dog alerts on an item, then we need to thoroughly check that item out."
Flights had to be delayed Tuesday afternoon because hundreds of passengers were still waiting to get through security when officials closed three of the security checkpoints.
The airport was returning to normal by 3:30 p.m., but passengers quickly discovered the security disturbance was putting them way behind schedule.
"There are no taxis," said Susan Inglis, who had gotten off a Northwest flight from Phoenix and was trying to go pick up her son.
Inglis, of St. Paul, said passengers getting off flights were escorted in a long line to baggage claim. Then many of them couldn't leave because taxis and other vehicles couldn't get near the airport.
"I was just stuck there," Inglis said.
An airport in Bakersfield, Calif. was also shut down for several hours Tuesday after what turned out to be another false alarm.
Authorities found some suspicious material inside a piece of luggage, but it turned out to be five soft drink bottles filled with honey, they said.
A passenger's suitcase tested positive for TNT at Bakersfield's Meadows Field during a routine swabbing of the bag's exterior, Kern County Sheriff Donny Youngblood said. When TSA officials opened the bag, they found bottles filled with an amber liquid, he said.
Investigators said the bag's owner, Francisco Ramirez, 31, is a gardener from Milwaukee who has been cooperating with authorities. He flew to Bakersfield Dec. 23 to spend Christmas with his sister and was returning Tuesday when the alarm sounded.
When TSA agents opened one of the bottles and tested the contents, the resulting fumes nauseated them, Youngblood said. Both were treated and released at a local hospital.
"It's encouraging that the system did work, because something is not right there," Youngblood said. "The system worked the way it was supposed to, but it just takes time when you close an airport -- and it costs a lot of money."
All flights into and out of Meadows Field were canceled for much of Tuesday as authorities searched the terminal for other potential explosives.
The Los Angeles County Sheriff's Office bomb squad was expected to perform further tests on the honey to determine why a false positive was recorded. Bakersfield is about 110 miles north of Los Angeles.
Investigators want to know whether any chemical Ramirez uses in his gardening work could have left traces of potential explosives. They will also run tests on the honey to see if the smoke beekeepers use to subdue the insects could have triggered the false positive test.
Ramirez was not arrested Tuesday. Authorities initially questioned his immigration status, but U.S. Immigration and Customs Enforcement spokeswoman Virginia Kice said Tuesday afternoon that Ramirez is a legal permanent resident of the U.S.
(The Associated Press contributed to this report)