The incident earlier this month led to an evacuation of the residence while hazardous materials workers checked to confirm the presence of ricin in the woman's living quarters, cleaned them and eventually cleared the scene.
Hawkes said that federal attorneys had decided recently not to pursue charges against the woman, since her intention was to harm no one but herself and a family living upstairs was determined not to have been imperiled by her actions.
State attorneys also have reportedly declined to prosecute the woman.
Production of ricin, which can be a weapon of mass destruction, is considered a matter of federal law.
North Park is the police agency for North Logan and Hyde Park.
Ricin is highly toxic, and at high levels of exposure can cause severe diarrhea and fatal episodes of shock. Death typically occurs within three to five days of the initial exposure due to multiple organ failure.
The levels of ricin ingested by the woman proved to be low enough that treatment eventually cleared the substance from her body.
Hawkes said that the woman, who reportedly had been suffering back pain and mental health issues, has since been released to the care and custody of out-of-state relatives.