PORTLAND — The state attorney general is investigating the Oregon Health License Agency, a department that oversees the boards and operations of about a dozen professions.

The investigation began early last week, and four managers and two union-represented workers have been placed on leave, said Tony Green, spokesman for Attorney General John Kroger.

Green on Tuesday would not disclose the names of those put on leave or describe the allegations.

The Oregon Health Licensing Agency oversees boards and operations of about a dozen professions, such as athletic trainers, tattoo artists, electrologists and denturists. It employs about 30 and operates on a budget of about $3 million a year.

The investigation commenced following a complaint by the Service Employees International Union Local 503, said Edward Hershey, spokesman for the union that represents some of the agency’s employees.

“They were shocked by the things they saw and heard, and they blew the whistle,” said Hershey, who declined to provide details of what was seen and heard.