Kaiser and the union representing its mental health clinicians reached a tentative agreement today on a three-year contract. If ratified by union members, it will end a nearly six-month strike that the union says is the longest work stoppage by mental health care workers in U.S. history.

The 50 striking clinicians include psychologists, social workers, psychiatric nurses and chemical dependency counselors who are represented by the National Union of Healthcare Workers.

Picket lines have been halted as of today, according to the union, and therapists will return to work on Tuesday.

Information on when the ratification vote is expected was not immediately available.

The Kaiser workers launched the strike in August, accusing their employer of understaffing its mental health clinics and not doing enough to attract new hires who could ease overwhelming caseloads. The union was fighting for higher salaries and better retirement packages.

Kaiser, in a statement, said that it looked forward to hearing the results of the ratification vote.

“Kaiser Permanente has the deepest appreciation and gratitude for our mental health professionals and the extraordinary care they provide to our members so we are pleased to have reached a tentative agreement with NUHW,” Kaiser said in a statement.