Byrd said Goff was arrested this past week and released on $10,000 bond. No trial date has been set.
The Mississippi Press reports that two other people arrested along with Goff have not been identified because they are cooperating with the investigation.
Byrd said authorities have issued a warrant for Memphis Shane Riddle of Brewton, Ala., who they believe accepted the stolen parts in exchange for OyxContin.
Byrd said investigators believe Riddle had subcontractor workers stealing the parts in exchange for drugs for the last five years.
"It could be as much as $500,000 worth of fittings," said sheriff's department Sgt. Robert Blocker said Monday. "We think he was repackaging the fittings and selling them to wholesalers in Alabama and Florida."
Blocker said at least eight people could have been involved in the parts thefts.
"More charges and arrests could follow," Blocker said.
Blocker said Goff was charged with embezzlement because "it was property that came to his care, custody or control by means of his employment."
Mark Richards, Triad Electric safety manager, said Goff was employed with his company at the time of his arrest, but has since been terminated.
"We are cooperating with Chevron security and the sheriff's office," Richards said.
Steve Renfroe, Chevron spokesman, said plant security guards discovered the thefts.
"We immediately turned it over to the sheriff's department, who arrested them," Renfroe said. "We have, and are continuing, to fully cooperate with the sheriff's department."
