TULSA, Okla. >> The phones rattled with the sound of an explosion. It was Sept. 11, and some of the traders at an energy company here had been speaking with colleagues at a financial company in the World Trade Center in New York. Suddenly, routine business calls became frantic dictations of final messages to loved ones. Then the lines went dead.

In a strange twist of fate, the office tower here where those messages were scribbled — rising 52 stories above this sprawling oil town — bears an eerie resemblance to those fallen twins in New York, one so striking that executives would joke that the architect who designed all three buildings had simply shrunk his blueprints.

Ten years after those phone conversations, the emotions and fears are still raw half a nation away from the site of the terrorist attacks, refreshed daily by the familiar profile of One Williams Center.

Some see the tower as an unplanned memorial. Others worry that it is a potential target.
“There is still fear,” said Linda Wagner, an accounting clerk who works in the building. “We are a miniature version in the middle of the country.”

As the anniversary of Sept. 11 approaches, the energy firm that owns the building, the Williams Cos., remains so concerned about the similarity that it has tried to keep the connections secret. Even longtime employees making their way inside still take care not to let their eyes linger upward too long.

Some cringe at the sound of passing planes, with one saying, “It makes your heart stop.”

The story of this office building in the dusty southern plains — known locally as the BOK building, after Bank of Oklahoma, a tenant — is one of an unlikely maze of connections tying people here to the attacks in New York.

“You never realize until something like that how interconnected we are,” said Keith E. Bailey, the former chief executive of the Williams Cos., who had visited the World Trade Center just a day earlier, on Sept. 10, with a team of employees.

The legacy of the attacks is visible here still. Workers shuffle past concrete bomb barriers on their way in and wear ID badges. And Williams officials, citing the concerns of their security officers, became so worried about becoming a target that they recently refused to answer questions and had this reporter escorted from the building.

“We must take into consideration how exposure like this might raise our risk profile, regardless of the remoteness of something actually happening,” Jeff Pounds, a spokesman for Williams, wrote in an email.

The BOK, the tallest building in Oklahoma, cried for attention when it was built 35 years ago in a decaying part of downtown. Originally, there were two smaller towers in the plans by Minoru Yamasaki, the architect who designed the World Trade Center. But shown a model, the head of the Williams Cos. picked up one of the towers and stacked it on the other. The end result was a single 667-foot building — nearly half the size of the twin towers.

The building, part of a much larger complex, was completed in 1976 at a cost of $86 million, three years after the World Trade Center. The resemblance between the towers stretched from the arched plaza at the base to the boxy windows at the top and along the long vertical lines that defined the facade.

Dale A. Gyure, an associate professor of architecture at Lawrence Technological University in Michigan, who is writing a book about Yamasaki, said the tower was the most similar of several around the country that shared features with the World Trade Center, including buildings in Buffalo, N.Y., Minneapolis, Seattle and Richmond, Va.

“He sort of developed a formula after the World Trade Center for his taller buildings,” Gyure said. “They all belonged to a family visually, but also structurally.”

Local news articles from the time make no mention of any comparisons with the gleaming new buildings to the east, but one, headlined “Williams Plans Against ‘Towering Inferno,”’ declared that the building would be “one of the safest office towers in the world when completed.”

On the morning of Sept. 11, 2001, that sense of invulnerability was shattered. After the plane strikes, some employees at Williams reached out to employees at Cantor Fitzgerald, a business partner, who described the chaos around them as they waited to be rescued. When it became clear that help would not arrive, a few started giving messages to be conveyed to their children and spouses.

“It was incredibly emotional,” said Bill Hobbs, who ran the energy trading division for Williams at the time. “That went on I don’t know how long, it seemed for hours, before the lines all went dead.”

Even before the buildings fell, the company had pledged a $1 million donation for what became the

September 11th Fund. Afterward, the company offered to set up a phone bank for Cantor Fitzgerald — which lost 658 employees in the attacks — to handle the flood of calls from family and friends.

Employees volunteered around the clock, some sleeping in offices between shifts.

The same questions came up again and again. “There was a lot of venting and a lot of frustration, and our employees really just listened because you couldn’t say, ‘I’ve got to hang up I’ve got another call coming in,”’ Hobbs said. “We didn’t have any answers to give them, but that didn’t stop them from asking questions.”

 And Bailey, the former chief executive, tried to assure his employees that just because the building resembled the twin towers, it was not at risk. “That’s not why someone would attack,” he said.

Still, employees remember pausing to look up at the building as they entered and envisioning the same scene that had been looped endlessly on television after the attacks.

“Every time I would go to work, I would look up and just picture it in my head, picture the planes going in,” said Lea Ann Forbes, who works at Bank of Oklahoma.

Even though Williams omitted any reference to Yamasaki or the World Trade Center from a news release about the 30th anniversary of the building several years ago, others here speak with pride about the shared lineage. “Its such an emblem of what was,” said Charlene Stroud, a production analyst for Williams. “Somehow we’re part of that memory.”