MONTREAL -- Four employees, five patients and a doctor at a Laval hospital have all tested positive for COVID-19 in the past week.

The union for the health-care workers at the Cite de la Sante Hospital north of Montreal said the spread may be due in part to employees working in multiple units at the same hospital.

"There is a team of workers who work in other units on the fifth floor," said CISSS de Laval-CSN's Marjolaine Aube.

Aube said at least one of the employees worked in several units, possibly exposing cancer patients to the potentially deadly novel coronavirus.

The union is calling for health-care workers to be assigned to one unit and stay there to prevent the spread.

"The response is simple," said Aube. "Post workers in one unit."

In August, Quebec Health Minister Chistian Dube announced that employees would no longer go from one long-term care facility to another starting in the fall.

The union would like similar measures in hospitals.

The CISSS Laval did not respond to CTV requests for comment, but the union said infected patients have been moved to the hospital's dedicated hot zone, and visitors to affected units have been encouraged to get tested.