The Los Alamos National Laboratory in Los Alamos, N.M. (The Albuquerque Journal via AP)

A former Energy Department employee was sentenced to 18 months in prison after offering to help a foreign government infiltrate the agency’s computer system to steal nuclear secrets and then attempting an email “spear-phishing” attack in an FBI sting operation.

Charles Harvey Eccleston, an environmental scientist formerly employed by the department and the Nuclear Regulatory Commission, pleaded guilty in February to one charge of attempting to damage protected government computers. Eccleston was arrested in March 2015 by Philippine authorities.

Eccleston, 62, a U.S. citizen, was terminated from the NRC in 2010, prosecutors said. In January 2015, they said, he targeted more than 80 Energy Department employees in Washington and at four national nuclear labs with emails containing what he thought were links to malicious websites that, if activated, could infect and damage computers. The FBI said that no malicious code was transferred.

The FBI sting was launched after Eccleston offered in April 2013 to provide an unnamed foreign government with more than 5,000 email addresses of all Energy Department employees for $19,000, or else he would offer the information to China, Iran or Venezuela, according to prosecutors.

Eccleston provided undercover FBI employees with 1,200 publicly available email addresses in exchange for $9,000, which he was ordered to repay, authorities said.

Prosecutors said Eccleston’s offense revealed some of the significant risks and the ease with which cyberattacks “can be constructed and carried out.”