Steele stands accused of "aiding the enemy" by providing detainees with unmonitored mobile phones between October 2005 and October 2006, said a US military statement released on Thursday.
Other charges include having an improper relationship with a translator and with the daughter of a detainee and violating an order against keeping pornographic videos.
The offences were alleged to have occurred between October 2005 and February 2007.
"These charges are merely an accusation of wrongdoing. Lieutenant-Colonel Steele is presumed innocent unless and until he is proved guilty beyond a reasonable doubt of any alleged offence," the military statement said.
Steel was the commander of Camp Cropper, a US detention facility outside Baghdad which holds "high value detainees".
Saddam, who was executed on December 30 after being convicted of crimes against humanity by an Iraqi court, received medical treatment at the prison but was not a permanent inmate.