FROM CNN WIRES:

(CNN) - About 7,000 patients of a Tulsa, Oklahoma, dental practice were being notified they could have been exposed to HIV and hepatitis over the past six years, health authorities said Thursday.

Dentist W. Scott Harrington voluntarily stopped practicing when the joint investigation by the Tulsa Health Department and the Oklahoma State Department of Health began, the Tulsa agency said in a statement. "The dentist is cooperating with investigators through his attorney," the department said.

According to the State Board of Dentistry, the investigation into Harrington's practice found "numerous violations of health and safety laws and major violations of the State Dental Act," the health department said.

This morning, CNN's Ed Lavandera reports on the latest in the investigation on "Early Start."

READ MORE: 7,000 warned of potential HIV, hepatitis exposure