With fears persisting that seaports are among the most vulnerable avenues for dangerous weapons to enter the country, and growing criticism of efforts to protect the borders, the port of Baltimore highlighted yesterday a piece of equipment that experts say can help.

A powerful X-ray machine that can see through a foot of steel, bought by U.S. Customs and Border Protection for $6 million 18 months ago and brought to Baltimore in January, can scan up to 140 cargo containers a day at the state's marine terminals.

Customs officials responsible for searching for bombs and other dangerous material, as well as drugs and other contraband, say they have found nothing inside the containers since the machine, called the Eagle, has been wheeled around the state's Seagirt Marine Terminal. But between the X-ray machine and an older, less powerful gamma ray machine more common at U.S. ports, officials are able to scan 14 percent of the containers that sail into the Baltimore port a year, about twice the national average.

"Close to 140,000 cargo containers arrive here at the port each year," said Customs' Commissioner Robert C. Bonner, who came to Baltimore to show off the high-powered machine. "I look forward to working with all of you here to ensure that the port of Baltimore has the manpower and technology it needs to protect this port."

The machine is owned and operated by U.S. Customs officials, but the event allowed Gov. Robert L. Ehrlich Jr. and his chief transportation and homeland security officers to claim Maryland as one of three states with such powerful X-ray machines, which are among the most advanced mobile technology available.

With more powerful equipment in the works, Customs has requested bids for more equipment that will be spread among the nation's ports of entry.

After a few months of the Eagle in operation, state and Customs officials said it was time to publicly unveil it.

The demonstration was held on the heels of a report by the Government Accountability Office that said the nation's 361 seaports remain vulnerable to terrorists despite the money and effort put into protection since the 2001 attacks. The report was presented last month to Congress, where bills are pending to add more defenses.

Ships must notify Customs and the Coast Guard when they are ready to leave a foreign port or arrive in a U.S. port and provide information on crews and cargo. The federal agencies flag suspicious cargo for inspection, which before 2001 was largely done by physically opening containers for a look inside.

Among new initiatives, government watchdogs have specifically criticized as wasteful or slow-moving the homeland-security grant program, which doles out money for training and equipment, and a container program, which involves inspecting the metal boxes and sealing them overseas before they reach U.S. borders.

Bonner, a former federal judge and drug enforcement official who was sworn in to lead Customs two weeks after the Sept. 11, 2001, terrorist attacks, defended the government's work since then at the ports, saying all containers considered suspicious are now inspected. That's no small undertaking considering that an average of 25,000 containers are imported through U.S. seaports a year.

F. Brooks Royster III, in his second day as the port's executive director, said $17.6 million in state and federal money has been dedicated to Maryland's defenses. Some of the items to be purchased include new fencing around the port, surveillance equipment and a patrol boat.

"Security at ports has become the No. 1 priority," he said.

Ehrlich said, "We are light-years from where we were just a few short years ago."

The group of officials took turns climbing aboard the 180,000-pound Eagle, a 42-foot- long, 21-foot-high behemoth shaped like an upside-down U that slowly rolls on rubber tires over 20-foot and 40-foot metal containers on the pier.

With the "X-ray on" light flashing red, one Customs agent drives and a second sits inside and monitors a screen showing an image of the boxes' insides. It can see through the cargo and highlight dense - potentially radioactive or nuclear - material.

Its manufacturer, Los Angeles-based Rapiscan Systems, says the device is a bigger, more powerful version of the screeners used at the nation's airports to peer inside passenger baggage and can scan a 20-foot box in 30 seconds.

Peter Kant, a Rapiscan vice president of government affairs, said his company and others have more powerful machines that cannot be wheeled around as needed in a sprawling port. Rapiscan and others also have machinery in development that will be able to provide an even better-quality image and pick up what type of dangerous material is inside a container.

The Eagle cannot, for example, differentiate between some medical equipment surrounded in lead and some more dangerous materials, possibly leading to false alarms.

The technology for the Eagle, which also is in use in Savannah, Ga., and El Paso, Texas, was developed in the mid-1990s at the direction of Customs. A prototype was deployed at the port of Miami. The machine is used with or replaces the lower-power gamma machines, now used at about 140 to 160 U.S. ports, and was developed originally to detect smuggled goods such as drugs stowed in hidden compartments.

"There's no silver bullet," said Jim Engleman, Customs' director of field operations in Baltimore. "This is pretty good. We can use it all day X-raying containers as they come off the ships and park it over to the side at night."