WARWICK — Vayl Oxford spends his time thinking about how vulnerable this country is to a nuclear attack.

But his fears go further than the detonation of a nuclear bomb. He worries about the more likely threat of “dirty bombs,” a conventional explosive device with radiological material, set off in a city center or a popular tourist destination. Such an explosion would kill and injure civilians and the emergency crews rushing to help them. And, he said, it would leave an aftermath of fear that would linger and ruin the area as powerfully as the bomb.

This is something that Rhode Island, and other states, must take seriously, said Oxford, the director of the U.S. Domestic Nuclear Detection Office, who visited the state Friday at the invitation of U.S. Rep. James Langevin.

As head of the two-year-old agency, Oxford leads a staff of agents from the FBI and members of the Defense Department, the State Department, the Energy Department and the Nuclear Regulatory Commission working together on one goal — looking for the vulnerabilities to radiological attacks and coming up with ways to prevent them.

There is vulnerability in dismissing the threat of dirty bombs, but Oxford has found other serious problems: a dearth of screening of container cargo, which is a problem not expected to be fully resolved for another five years; a potential for terrorists to use small marinas to bring in deadly material; and an unsettling discovery that some states and cities have wasted untold amounts of money on screening equipment that doesn’t work.

Oxford has twice spoken before the House Homeland Security Subcommittee on Emerging Threats, Cybersecurity, and Science and Technology, which Langevin chairs. The congressman invited Oxford to Rhode Island to talk to first responders about how his agency could help them.

When Warwick Police Chief Stephen McCartney wondered about the possibility of a terrorist bringing a nuclear device through small marinas, such as the ones in his bayside city, he touched on a real concern of Oxford’s.

While the federal government is concentrating on screening the cargo coming off large container ships in the nation’s largest ports, Oxford is worried about the smaller marinas and air strips. A terrorist trying to bring hazardous materials into the United States will want to keep the materials in his or her possession, he says.

“I worry a lot about small maritime craft and aircraft,” he said. “We’re working aggressively with the Coast Guard. We want to increase the capacity of the Coast Guard to get [screening] technology into the hands of local law enforcement.”

This touched on another major problem that Oxford discovered early in his leadership of the Nuclear Detection Office. Although state and local departments were meeting federal requirements by buying radiological detection equipment, they were often buying junk because there were no standards and testing of the equipment, he said.

Oxford has used his office to establish those tests and standards, so the office could make recommendations and offer training using the equipment.

In Rhode Island’s case, the detection equipment used by the state police, decontamination teams and hazardous materials responders is serviceable, he said.

“Some of the Rhode Island equipment could be replaced,” Oxford said. “Some of it could be better.”

Oxford said his office will work with the Rhode Island Emergency Management Agency on recommending equipment. Robert J. Warren, the state executive director, said the state began working last year on its plan for dealing with radiological dispersion devices, or “dirty bombs,” and is seeking $200,000 in homeland security money this year for upgraded equipment.

Langevin said he wanted to bring Oxford’s knowledge to the Rhode Island first responders, so they knew they had a direct connection for advice and assistance. “It’s also important to remind everyone that it’s the first responders who would respond if there’s a nuclear or radiological attack,” and they have to have equipment that can detect radiation, he said.

amilkovi@projo.com