HOUSTON, Texas (AP) -- A college student's checked luggage on a Continental Airlines flight from Argentina contained traces of dynamite, authorities said, in one of four security incidents Friday involving U.S. flights.
An American Airlines flight from England to Chicago was forced to land in Bangor, Maine, for security reasons, and a U.S. Airways jet was diverted to Oklahoma City after a federal air marshal reportedly subdued a passenger who was involved in an incident with a flight attendant, officials said.
An Aer Lingus flight from New York to Dublin was evacuated Friday morning during a scheduled stopover in western Ireland following a bomb threat that turned out to be unfounded, officials said.
Federal authorities are investigating why the student, who got off the Continental plane in Houston before it continued to Newark, New Jersey, had the explosive residue and what he intended to do with it, FBI spokeswoman Shauna Dunlap said.
The dynamite residue was found during a luggage search in a federal inspection station at Bush Intercontinental Airport shortly after Flight 52 landed at about 6 a.m. Marlene McClinton, spokeswoman for the Houston Airport System, said a bomb-sniffing dog "had a hit" on explosive residue during a further search.
She said Customs and Border Patrol and the FBI shut down the customs area and began questioning the passenger who had the luggage. The identity and age of the passenger, a man, were not released.
Houston Fire Department Assistant Chief Omero Longoria said the man told fire officials that he works in mining and often handles explosives, so that would explain the residue. He said federal officials were investigating whether the man's explanation was true, and the fire department's role in the probe ended upon determining the man's bag did not contain a bomb.
Dunlap declined to release specifics, but confirmed that the explosive was dynamite. Dunlap also said the man was from Connecticut and attends Lafayette College in Easton, Pennsylvania.
Continental spokeswoman Julie King said the CBP contacted the carrier when the dog detected the explosive. She said the flight left Buenos Aires, Argentina, and had 173 passengers.
After landing at Newark Liberty International, Flight 52 was kept from the terminal as a precaution, said Marc La Vorgna, an airport spokesman.
'Concerns addressed'
In a second incident, Federal Aviation Administration spokeswoman Arlene Murray said American Airlines Flight 55 out of Manchester, England, was diverted to Bangor for security reasons.
"The TSA learned of a reported threat to the aircraft while it was en route," Transportation Security Administration spokeswoman Andrea McCauley said, declining to give further details.
McCauley said FBI agents were interviewing passengers and crew members. She added that officers with dogs trained to detect explosives were also checking the plane.
The Boeing 767 carrying 167 passengers and 12 crew members was diverted at the request of the Transportation Security Administration, airline spokesman John Hotard said.
"Nothing is wrong. We will put a new crew on it, and the flight will continue to Chicago," Hotard said. "The TSA had a security concern about the flight, and the concern has been addressed."
Hotard declined to say whether any passengers were removed from the flight, but said the crew needed to be changed because of restrictions on how many hours they can work.
At Oklahoma City's Will Rogers World Airport, law enforcement officers were questioning the passenger involved in the incident that led to the diversion of the U.S. Airways flight, airline spokesman Morgan Durrant said. The Charlotte, North Carolina-bound flight had left Phoenix at 6:15 a.m.
Durrant did not disclose the nature of the problem between the passenger and the flight attendant. Officials at the airport and the FBI did not immediately return telephone calls.
A passenger interviewed by a television station said an air marshal tackled the man, but that it wasn't clear what prompted the incident.