SEATTLE - The Port of Seattle set up a perimeter of nearly a half mile around one of its terminals Wednesday after bomb-sniffing dogs indicated that two containers from Pakistan could contain explosives.

Bomb experts determined there was no radiation after they inserted a camera inside the containers, said port spokesman David Schaefer.

However, police and bomb experts were still at the scene in the late afternoon, removing boxes from the containers.

A bomb squad used explosive charges to cut into the containers, which may have detonated any explosives therein.

The Port of Seattle bomb squad apparently did not believe there was a chance of causing a larger blast by using the small charges to gain access to the containers.

KING

Two firefighters edge their way around a suspicious container at the Port of Seattle.

"There was a suspect container, two of them, taken off the ship because there were questions about the manifest," Schaefer said. "The bomb-sniffing dogs did what bomb-sniffing dogs do, and it caused us to be worried there might be explosives."

Dozens of non-essential personnel were evacuated from Terminal 18, on Harbor Island south of downtown Seattle. Officials with Todd Shipyards, which is adjacent to the terminal, decided to close for the day, and sent employees home.

The U.S. Customs and Border Protection said agents had been using a "gamma-ray" device to peer through the containers' steel walls to determine what they contained. Some of the items did not appear to match what was listed on the containers' manifest.

The Rotterdam ship belongs to China Shipping. It had stopped in Hong Kong, Shanghai and Pusan before arriving in Seattle on Monday, according to a U.S. Customs agent.

KING

Terminal 18 is one of the largest container terminals in North America.

The containers were reportedly designated for inspection long before they arrived. The fact that they were from Pakistan, however, was part of the reason, according to the agent.

Terminal 18 covers nearly 200 acres, making it the port's largest container terminal and one of the largest in the nation. It serves more than 20 steamship lines and receives more than 40 vessels each month.

Washington Sen. Patty Murray said in a statement released late Wednesday afternoon:

Today's incident at Terminal 18 should raise red flags across our country and in the halls of Congress about the vulnerability of our cargo containers and of our ports.

Luckily for the people of Seattle - and our national economy - today's scare appears to be a false alarm. I applaud our port staff and cargo inspectors for a job well done. They did a great job in a tense situation.

But our port workers, inspectors and the American public deserve to know that the cargo entering our country each day is safe. To protect America, we have to increase our security and know what is in our cargo containers.

KING

That's why the Senate leadership must take up and pass the bi-partisan cargo security legislation that I wrote with Senator Susan Collins of Maine last year. The GreenLane Maritime Cargo Security Act has already passed a key Senate Committee and the House of Representatives, but the Senate leadership refuses to make our security a priority.

Each year, six million cargo containers enter U.S. seaports, and as we saw today, we frequently don't know what is in those containers or whether they have been tampered with.

Today's incident shut down a terminal for several hours, but a terrorist attack on our ports could cause devastating loss of life and the shut down of ports and economic activity across the country.

Back in Washington, D.C., it might feel like the dangers at our ports are a distant concern. But standing in downtown Seattle today, we know that the threat is real and close at hand.

It is time to do the right thing and pass the GreenLane Act for the safety and security of America.