Part of a ticketing area at LaGuardia Airport was evacuated Friday after a piece of checked luggage containing a gas mask and a cylinder filled with a white powder tripped an alarm on an X-ray machine in a nearby baggage screening room, said Tom Wilkins, deputy federal security director of the Transportation Security Administration.

Wilkins said that at about 12:15 p.m. screeners near the D ticketing area were X-raying the luggage belonging to a passenger on American Airlines Flight 721 when an alarm tripped, signifying the luggage should be checked by hand.

Wilkins would not say what tripped the alarm, but he said a screener found a plastic bag containing a gas mask and a nine-inch cylinder filled with a white powder inside the luggage. A screener alerted authorities, who immediately quarantined the area, the Wilkins said.

Initial tests for anthrax were negative, but the tube was taken away for further examination and testing by Port Authority officers.

Six Tranportation Security employees were immediately decontaminated at the scene, but Wilkins said, "There's no evidence of any infection." The baggage screening area, a narrow room with a mock wall, was also decontaminated by Port Authority officers.

Wilkins said one screener reported a red rash on one of her hands after the incident, which he said may or may not be related to the powder. The screener was treated with alcohol and not taken to the hospital, Wilkins said. He said the rash could have been caused by the latex gloves the screener was wearing.

"All my screeners are alert and they do an excellent job," Wilkins said.

The terminal was not closed, but about half of the ticketing area around the baggage screening room was roped off. There were no flight delays.

The owner of the bag had already departed on a flight bound for Dallas-Fort Worth. Wilkins said the passenger would be met in Texas by officials, including members of the FBI.

Asked why the passenger took off without the bag, Wilkins said it's not that unusual.

The incident brought dozens of fire, police and emergency personnel and triggered a storm or rumors in the airport, including one that a handler had a convulsion and another than three baggage handlers were injured. Those are just rumors, Wilkins said.

Steve Traveras, a baggage checker, said he saw a rush of emergency vehicles when the incident happened. "I didn't run, but I went away as fast as I could. " An hour later he was back on his shift.

Mickey Bennett, 45, a marketing/research professional from Port Washington, said, "If it were that big of a deal, this place would have been evacuated."

Chuck Bicco, 68, of Denver, arrived on a United Flight and saw the fire trucks.

"With the heightened security I just thought it was par for the course but obviously it isn't."

Asked if he was scared to be in New York, he said, "No, I don't sweat terrorists or anything like that . If it happens it's going to happen."