In addition to Public Service Electric & Gas' Salem-Hope Creek plants, Mobley worked at the Peach Bottom, Limerick, and Three Mile Island Island plants in Pennsylvania, and at Calvert Cliffs in Maryland, according to an e-mail from Neil Sheehan, a spokesman for the U.S. Nuclear Regulatory Commission.
U.S. Sen. Robert Menendez (D., N.J.) sent a letter to the chairman of the NRC yesterday inquiring whether Mobley could have obtained information valuable to a terrorist organization and whether the background-check process had missed any warning signs.
"I want to know if the system failed in this instance, and if changes need to be made," he wrote.
Sheehan said the commission was investigating what level of access Mobley had at the plants.
He was a contractor with Local 222 of the New Jersey Laborers Union in Camden for projects in Salem County.
"He had full clearance to go where he needed to be," said chapter business manager Curt Jenkins. "You have no way of knowing what somebody's thinking. He went through the strenuous background checks that everybody else has to go through."
Sheehan said, "A laborer typically would not have access to any security-related or sensitive information."
Background checks include criminal history, drug testing, employment verification, and psychological assessments. The companies - not the NRC - carry out the background checks and are required to do ongoing behavioral observation.
PSE&G spokesman Joe Delmar said Mobley worked as a contract laborer during refueling outages from 2002 to 2008 and satisfied federal security requirements.
Federal authorities told state homeland security officials that there was no security breach involving Mobley at the nuclear plants, according to Mike Drewniak, spokesman for Gov. Christie.
Jenkins said Mobley would have been put through a repeated background check each time he worked on a new job. He said such checks were thorough, going as far back as childhood.
"If there's anything there, they're going to find it," he said.
Mobley transferred from Philadelphia Local 322 in 2003 and suspended his union membership in 2008, telling Jenkins he was going to school. He did not say where or what for. Jenkins said he assumed Mobley was at a university in the region or "in the country at least."
He said Mobley was polite and hardworking.
"He always was mild-mannered," Jenkins said. "I never saw him angry or portray any sign that he would get violent."
Mobley's brother, Charles Beyah, also is a union member, in Atlantic County.
Contact staff writer Chelsea Conaboy at 856-779-3893 or firstname.lastname@example.org.
Inquirer staff writer Andrew Maykuth contributed to this article.