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.”...