Arrests Wednesday linked to the investigation of the Sept. 11 terrorist attacks had roots in a more than year-old state license fraud probe.

Court documents said a Pittsburgh driver's licensing examiner helped at least 18 men get permits to transport hazardous materials without the required tests from July 1999 to February 2000.

In some cases tests were waived under the pretense the drivers were transferring commercial licenses issued by other states, including Kentucky, Kansas, Michigan, Tennessee, Texas, Virginia and Washington state, according to the court documents.

A federal magistrate in Pittsburgh unsealed criminal complaints against seven men Wednesday after their arrests. Authorities in Washington, D.C., said three other men were arrested Wednesday as the result of warrants issued in western Pennsylvania.

The arrests in Missouri, Michigan and Washington state came after FBI warnings that terrorists may strike next using chemical or biological weapons. None of those arrested Wednesday have known connections to the attacks on the World Trade Center and the Pentagon, said Justice Department spokeswoman Susan Dryden.

The Pittsburgh examiner -- identified in the documents only as an unidentified witness in the case -- told authorities he received $50 to $100 for each person he helped.

The examiner dealt with a middle man identified in court records as Abdul Mohamman, who brought the examiner at least 18 people who fraudulently obtained the hazardous-material licenses. Two other people allegedly received commercial driver's licenses without the hazardous materials designation.

The Pennsylvania Department of Transportation began an investigation after learning in February of last year about three people who attempted to transfer Pennsylvania commercial driver's licenses to Washington state.

On Sept. 20 of this year -- nine days after the attacks -- state Transportation Secretary Brad Mallory contacted state Attorney General Mike Fisher about the investigation.

Men identified only as Hussain Al-Obaidi, Samir Almazaal, Akeel Al Aboudy, Hatef Al-Atabi, and Sabah Al Hachami allegedly claimed to have commercial licenses in Michigan when they obtained their Pennsylvania licenses, according to court documents. Ali Alazawi, also known as Al Gazawi, and Mustafa Al-Aboody allegedly claimed to have Washington State licenses when they got their Pennsylvania licenses.