Howard McFarland Fish, 21, was charged with carrying an explosive aboard an aircraft and was in the custody of U.S. Immigration and Customs Enforcement. Federal authorities have determined that his actions were not acts of terrorism, ICE spokeswoman Luisa Deason said in a statement.
Inside Fish's checked bag, customs agents found a partial stick of dynamite and ammonium nitrate, more than enough explosives to bring down a plane. And in his carry-on bag they found a detonating fuse, reports CBS News correspondent Bob Orr.
Houston Fire Department Assistant Chief Omero Longoria said Fish told authorities he works in mining and often handles explosives. Longoria said federal officials were investigating whether the explanation was true.
Bill Waldock, aviation safety professor at Embry-Riddle Aeronautical University in Arizona, said the incident could have been disastrous and raises questions about security in overseas airports. Dynamite can be unstable if it's old, he added.
"You're in a pressurized airplane, you get a detonation in the cargo hold, it could blow a hole in the airplane big enough to bring it down," he said.
The dynamite 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 ICE officials and the FBI shut down the customs area and began questioning Fish, one of 173 passengers on the flight.
The U.S. Attorney's Office in Houston said Fish, of Connecticut, would appear before a federal magistrate Monday. Carrying an explosive aboard an aircraft carries a maximum penalty of 10 years in prison and a fine of up to $250,000.
Fish is a psychology student at Lafayette College in Easton, Pa., said Roger Clow, the college's director of communications. He declined to answer other questions about Fish, citing privacy concerns.
In other incidents:
The Manchester-to-Chicago flight, American Airlines Flight 55, was diverted to Bangor for security reasons, Federal Aviation Administration spokeswoman Arlene Murray said.
The plane landed on a remote taxiway and passengers were taken by bus to a holding area, said airport manager Rebecca Hupp. State police provided bomb squad dogs, and local police provided additional assistance.
"The TSA learned of a reported threat to the aircraft while it was en route," TSA spokeswoman Andrea McCauley said, declining to give further details. FBI agents were interviewing passengers and crew, she added.
Marcinkiewicz, of the FBI, declined to elaborate on the source of the threat, or to say whether officials believed it to be legitimate.
Passengers said they had not seen any disruptions during the flight. Amy Chignell of Redditch, England, said she sat next to the man who appeared to be the subject of concern and did not see him do anything out of the ordinary, although he went to the restroom a few times.
Tom Roseberry of Seattle said passengers were told they were landing in Maine because a member of the crew was ill. But he said passengers began to suspect something else was going on when they saw a fighter jet zoom by.