WASHINGTON – The FBI has turned to an Iranian-born chemist – who fled the fanatical Islamic revolution there in 1979 – to head a new unit devoted to stopping weapons of mass destruction aimed at the United States.

FBI Director Robert Mueller’s appointment of Los Alamos National Laboratory scientist Vahid Majidi to head the newly created directorate on WMDs is a break from the bureau’s tradition of promoting from within. Majidi, 44, declined to give The Post his opinions on the furor over Iran’s nuclear program, saying his focus will be on a wide variety of threats and would not be on a specific country or program.

He has a simple mission: “Our priority is to stop use of weapons of mass destruction. We do not want them to be used in the U.S.”

Born in Tehran, he moved with his brother to Urbana, Ill., in 1979 when he was a high-school senior, because his parents feared the fall of the shah and the ayatollahs’ takeover would lead to university closures and a military draft.

WMD experts say Majidi’s appointment should be welcome inside the bureau. “The bureau has a lot of resources and expertise, but they don’t have a lot of people with degrees in chemistry or nuclear physics. They need people who can tell, for example, if there’s been a complaint that a foreigner is buying a beer fermenter, whether it’s a weapons-of-mass-destruction problem, or it’s just someone trying to buy a beer fermenter,” said Ivan Oelrich of the Federation of American Scientists.

Majidi, a father of two teens, received chemistry degrees at Eastern Michigan University, where he met his wife, Jeanne, and earned a Ph.D. in spectroscopy at Wayne State University. He taught at the University of Texas and the University of Kentucky. He went to work at Los Alamos in 1997 and said that despite his academic background, he became “increasingly involved in national-security issues” while at the labs.

In 2001, he was brought in by the FBI as a technical adviser on the task force investigating the anthrax attacks on media companies – including The Post – and politicians.

He said the “FBI was very eager in trying to get the best science possible” to help solve the baffling case.

His work on the anthrax probe led to his 2003 appointment as chief science adviser to the Justice Department, where he frequently briefed then-Attorney General John Ashcroft. Majidi returned to Los Alamos in 2005 as chief of the chemistry division, and was approached for the FBI job last December after the White House, following a recommendation from the 9/11 commission, ordered the creation of a bureau WMD division.

“This is clearly a deviation from my normal career path,” he said. “The WMD issue is a complex issue that requires problem-solving abilities – much like science involves complex issues that require problem-solving abilities.”

For now, he will have a long-distance marriage. Jeanne also works at Los Alamos and doesn’t plan to move to Washington until their oldest son, Alex, graduates from high school.

She said the only problem with the new arrangement is Majidi’s dry sense of humor in his e-mails.

“Sometimes he likes to say, ‘I’ll have to talk to you later, I’m busy saving the nation,’ ” – and these days, she doesn’t know whether he’s joking or not.

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PROFILE

Name: Vahid Majidi

Profession: Chemist

Born: Tehran, Iran

Came to U.S.: 1979

Family: Wife, two teenage children in Los Alamos, N.M.

Education: Eastern Michigan University, Wayne State University

Previous academic jobs: Professor at University of Texas and University Of Kentucky

Previous government jobs: Department of Agriculture, Department of Justice, Los Alamos National Laboratory

Hobbies: Running