TORONTO -- A TTC worker has tested positive for COVID-19, forcing up to 170 other employees to self-isolate.

The maintenance employee, who does not work on the TTC’s frontline, tested positive after returning home from a trip earlier this month.

The employee, who works at a facility in the TTC Hillcrest Complex, attended one shift on March 11 but was sent home sick and has not returned since. The TTC said the facility will now undergo a “through disinfection.”

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Between 130 and 170 employees have been asked to self-isolate until March 25 and not return to work until March 26.

A #TTCmechanic who does not work on frontline service maintenance is our first positive case of #COVID19 . Approx 130-170 employees are impacted by a self isolation and monitoring directive. 1/2 — TTCStuart (@TTCStuart) March 19, 2020

“This is an unsettling, unprecedented time at the TTC, but I want to assure you we are doing everything we can to fight the spread of COVID-19 and keep you and our customers safe,” TTC CEO Ricky Leary said in a statement on Thursday.

“Keep this employee and their family in your thoughts.”

Meanwhile, Mayor John Tory told CP24 that the transit commission is seeing a revenue decline of "tens of millions of dollars" per week during the pandemic.