Toronto Western Hospital has declared a fifth COVID-19 outbreak, this time in its emergency room.

According to a report in the Toronto Star, the outbreak was declared after five staff who work in the unit tested positive for the virus.

In a memo sent to staff on Wednesday, the hospital said that anyone who worked in the emergency room between April 20 and May 3 will now have to submit to mandatory testing as a precaution.

While the hospital said in the memo that “it is not always necessary to fully close a unit during an outbreak,” it did commit to taking a number of added precautions to limit the further spread of COVID-19 in the unit.

It said that going forward emergency room access will be restricted to “essential staff only” and that “PPE coaches” will be brought in to make sure “staff feel comfortable with donning and doffing PPE, proper mask etiquette, and physical distancing.”

They also said that they will be “improving social distancing cues and reorganizing common spaces to facilitate physical distancing.”

Toronto Western Hospital has previously confirmed four other outbreaks in wards within the hospital. Two of those wards were specifically used for COVID-19 patients while the other two were not.

Last week, University Health Network spokesperson Gillian Howard said 19 patients at the hospital were infected with the virus but only 10 remain hospitalized.

So far, 97 staff members at the hospital have tested positive for COVID-19 out of 3,743 tests.

“I think people should be sure of the fact that the University Health Network and Toronto Western Hospital have the highest standards of disinfection in place. It is an excellent, well-run hospital but one of the problems here is that once the virus gets inside a building and it is a building in which there are people who are fairly closely confined, it becomes a real management challenge to contain it,” Mayor John Tory told CP24 on Thursday morning. “I think they are doing their very best at that and I have great confidence in those people.”

There have been 73 COVID-19 outbreaks at hospital units across Ontario so far.

Those outbreaks have involved 294 confirmed cases among residents and 319 confirmed cases among staff.

An outbreak is defined whenever multiple cases are confirmed within a 14-day period under a new provincial definition.